Basic I-Biology (BIO101) book HANDOUTS / POWER POINT SLIDES in pdf

<b><span style="font-size: large;">Basic I-Biology (BIO101) book HANDOUTS / POWER POINT SLIDES in pdf</span></b><div> Handouts | Lectures | Contents | Books</div> <div> <br /></div> <div> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5CrVDOLnHDEeCcYL9_ljwPnAHKs8evOZv_lgGhMRyomKIsHdKoKVgcPyz4lSYpMJV7-gClIFmqoS5hAxEX9kMPdblBk4rnvQL5Nx6jH0CImBTSJUByi-Le0lQzlidRIwrB1a5cwf_mnk/s1600/Bio%252B101%252BIntroduction%252Bto%252BBiology.jpg" imageanchor="1"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5CrVDOLnHDEeCcYL9_ljwPnAHKs8evOZv_lgGhMRyomKIsHdKoKVgcPyz4lSYpMJV7-gClIFmqoS5hAxEX9kMPdblBk4rnvQL5Nx6jH0CImBTSJUByi-Le0lQzlidRIwrB1a5cwf_mnk/s1600/Bio%252B101%252BIntroduction%252Bto%252BBiology.jpg" /></a></div> <div> <br /></div> <div> <div> <br /></div> <div> Biology lecture # 1</div> <div> Levels of Life</div> <div> (From Atom to Biosphere)</div> <div> WHAT IS LIFE?</div> <div> Anything is living if:</div> <div> It can acquire energy from the environment, e.g., plants acquire energy using</div> <div> sunlight and carbon dioxide and animals gain energy by eating plants like</div> <div> goats eat plants.</div> <div> It is capable of reproducing itself, e.g., all animals produce young ones like</div> <div> lions produce cubs. Plants also reproduce seeds to give rise to new plants.</div> <div> Mutating / changing itself: all organisms have a property of mutations, i.e.,</div> <div> their heredity material – DNA changes itself during division or other times and</div> <div> the result is change in any characteristic of the organism. This characteristic</div> <div> may be beneficial or harmful; organisms survive better if mutation is</div> <div> beneficial and may die if it is harmful.</div> <div> BIOLOGY – THE STUDY OF LIFE</div> <div> Biology (Bio – life; logos – study, reasoning); biology is hence the study of life or living</div> <div> organisms. Biology is about exploring the living part of the world, e.g., studying about</div> <div> animals, plants and even microorganisms is biology.</div> <div> Biology have many subdivisions; for example, anatomy – the study of structures, physiology</div> <div> – the study of functions, microbiology – the study of microorganisms and many more.</div> <div> The exploration of life helps in understanding the phenomena of nature and effective</div> <div> utilization and management of natural resources. We can find solutions to various problems</div> <div> for example treatment for various diseases could be discovered, methods for energy</div> <div> production from biological materials may be found, e.g., few bacteria can produce fuel from</div> <div> grasses.</div> <div> LEVELS OF ORGANIZATION IN LIFE</div> <div> · Atoms</div> <div> · Molecules</div> <div> o Micromolecules</div> <div> o Macromolecules</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 2</div> <div> · Cells</div> <div> · Tissues</div> <div> · Organs</div> <div> · Organ-systems</div> <div> · Organisms</div> <div> · Populations</div> <div> · Communities</div> <div> · Ecosystems</div> <div> · Biosphere</div> <div> Diagram below:</div> <div> Biosphere</div> <div> Ecosystem</div> <div> Community</div> <div> Population</div> <div> Organisms</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 3</div> <div> Organ</div> <div> systems</div> <div> Organs</div> <div> Tissues</div> <div> Cells</div> <div> Molecules</div> <div> Atoms</div> <div> LEVELS OF ORGANIZATION IN LIFE – MORE DETAILS</div> <div> Atoms</div> <div> Greek: a, not; tom, to cut: The smallest component of an element that have all the properties</div> <div> of that element. In nature, 92 kinds of elements are present, out of which only 16 make the</div> <div> living organisms, called bioelements. Bioelements are Oxygen (O), Carbon (C), Hydrogen</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 4</div> <div> (H), Nitrogen (N), Calcium (Ca), and Phosphorus (P). These elements make 99% of living</div> <div> mass. Others ten elements make 1 % of total living mass named Potassium (K), Sulfur (S),</div> <div> Chloride (Cl), Sodium (Na), Magnesium (Mg), Iron (Fe), Copper (Cu), Manganese (Mn),</div> <div> Zinc (Nz), and Iodine (I).</div> <div> Atoms</div> <div> All living things consist of atoms, like all other forms of matter. Atoms consist of “subatomic</div> <div> particles”; charged or not charged. These include electrons which are negatively charged</div> <div> particles, protons which are positively charged and neutrons which have no charge. Protons</div> <div> and neutrons are present inside the center and the electrons revolve around these in orbits.</div> <div> Atoms do not live in isolation but join together to make molecules (compounds).</div> <div> Molecules</div> <div> Atoms join together by a process called “bonding” to each other to construct molecules.</div> <div> Bonding is of two types.</div> <div> ionic bonds</div> <div> covalent bonds</div> <div> In inonic bonding one atom gives one or more of its electron to the other atom which is</div> <div> called a donor and the other receive the electron called recipient. The donor atom then</div> <div> becomes positively charged and the recipient becomes negatively charged. In covalent</div> <div> bonding, however, the atoms share one or more of their electrons and these electrons revolve</div> <div> in the orbit of both atoms. Covalent bonding is more strong form of bonding.</div> <div> On the bsis of their size molecules are categorized into micromolecules and macromolecules.</div> <div> Micromolecules are the molecules with low molecular weight, e.g., glucose, water.</div> <div> Macromolecules are the molecules with high molecular weight, e.g., proteins, carbohydrates</div> <div> and lipids.</div> <div> An organism consists of enormous number of biomolecules different types. Though some</div> <div> organisms are unicellular, i.e., consist of one cell only. Many other organisms are</div> <div> multicellular, i.e., these consist of many cells.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 5</div> <div> Organelles</div> <div> Molecules make organelles. Organelles are sub-cellular structures, assemble together to make</div> <div> cells – the units of life, e.g., mitochondria, lysosomes, Golgi bodies, nucleus. For example,</div> <div> mitochondria of a cell (Singular: mitochondrion) is called “powerhouse” of the cell. This</div> <div> organelle is present in the cytoplasm of the cells and makes energy for the cells hence called</div> <div> “power house”. These are found in both plants and animals. Another example is nucleus</div> <div> present in almost all cells.</div> <div> Organelle: nucleus.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 6</div> <div> Cells – the basic unit of life</div> <div> All the living organisms consist of cells. Cells are called the basic units of life. Cells are</div> <div> specialized in their structure and functions. There are different types of cells present in the</div> <div> bodies of multicellular organisms. But some organisms like amoeba consist of only one cell.</div> <div> Cells are categorized based upon the placement of their nuclear material into prokaryotic and</div> <div> eukaryotic cells. Prkaryotic (Pro: old, Karyotic: related to nucleus) cells are those cells that</div> <div> do not have a true nucleus – it means that their nuclear material is not covered by a</div> <div> membrane. While eukaryotic cells have a true nucleus, i.e., their nuclear material is covered</div> <div> by a membrane called nuclear membrane. Sometimes a cell makes a whole unicellular</div> <div> organism, like Prokaryotes and Protists. A variety of cells makes a single, multi-cellular</div> <div> organism.</div> <div> Animals Cell</div> <div> Plant Cell</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 7</div> <div> Bacterial Cell</div> <div> Stem Cells</div> <div> These are the undifferentiated cells in which most of the genes are switched on and these</div> <div> have a potential to make almost all cells of the body. These cells are present in a few places</div> <div> in adult organism or present in the embryos. These are useful for human beings because these</div> <div> can be used in making organs of any type which may be damaged by for example a disease.</div> <div> Tissues</div> <div> These are the groups of similar kind of cells which perform a same function. The tissues</div> <div> perform a common function, specialized to the tissue. For example, epithelial tissue that</div> <div> makes the skin.</div> <div> Onion Epidermis (tissue)</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 8</div> <div> Organs and organ systems</div> <div> Tissues group and work together to make a unit called organ. Different tissues in an organ</div> <div> work differently to perform collective function of the organ. For example in stomach, there</div> <div> are muscle tissues that contract and relax for grinding and there are secretory cells which</div> <div> secrete gastric juices to digest the food. Collective action is the secretion of gastric juices and</div> <div> its mixing.</div> <div> Digestive system in humans</div> <div> In the simple to complex organisms, many organ-systems are present, for example, in humans</div> <div> digestive system, cardiovascular system, respiratory system and many more are present that</div> <div> work for a specific purpose. Digestive system consists of oral cavity, esophagus, stomach,</div> <div> intestine, pancreas, liver and rectum. Cardiovascular system consists of heart, vessels and</div> <div> blood.</div> <div> Organism</div> <div> Organ-systems join together to constructs organisms. In an organism, the organs and organsystems</div> <div> coordinate to perform the activities of the whole organism. For example, in humans</div> <div> brain control the activities of most of the organs and organ-systems. If a person is running;</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 9</div> <div> cardiovascular system provides it oxygen and nutrients, muscles contract and relax for</div> <div> movement and nervous system coordinate all of these functions.</div> <div> Population</div> <div> All organisms of a species living in an area at a particular time are called population, like all</div> <div> deer in a forest. Biologists study populations to explore the interactions between organisms.</div> <div> For example, interactions between male-male, female to female or else.</div> <div> Ducks in a local park</div> <div> Community & Ecosystem</div> <div> Different populations living in an area in a particular time, for example, in a forest plants,</div> <div> animals, algae, fungi live together are called a community. Populations interact with each</div> <div> other and also to the abiotic factors of the area to make Ecosystem, for example, a lake</div> <div> ecosystem.</div> <div> Plant community in a forest</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 10</div> <div> Biosphere</div> <div> The part of the world covered or inhabited by the living organisms is called biosphere. This is</div> <div> also called zone of life on Earth. Biosphere includes all ecosystems, like forests, lakes, oceans</div> <div> and valleys where biotic components exist.</div> <div> Exercise</div> <div> 1. Draw a flow chart to demonstrate the levels of organization in life.</div> <div> 2. Label various parts of atom in the following diagram:</div> <div> 3. Label various parts of a bacterial cell in the following diagram:</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 11</div> <div> Biology lecture # 3</div> <div> CELL ORGANELLES</div> <div> WHAT IS CELL THEORY?</div> <div> Cell theory in its modern form states:</div> <div> o All living organisms are composed of one or more cells.</div> <div> o Cells are the smallest living things, the basic unit of all living organisms.</div> <div> o Cells arise only by division in pre-existing cells.</div> <div> HOW CELL THEORY DEVELOPED?</div> <div> Cells were first described by Robert Hooke (Curator for instruments of Royal Society</div> <div> of London) in 1665.</div> <div> Leeuwenhoek (Textile Merchant) observed tiny organisms in pond’s water, called</div> <div> them animalcules.</div> <div> In 1809, de-Lamark proposed that nobody can have life if its parts are not cellular</div> <div> tissues.</div> <div> Robert Brown discovered nucleus in the cell.</div> <div> In 1838, Schleiden stated that all plants are aggregates of individual cells.</div> <div> In 1839, Schwann stated that all animal tissues consist of cells.</div> <div> In 1855, Virchow proposed that cells arise from pre-existing cells.</div> <div> In 1862, Pasteur provided experimental proof for the above.</div> <div> CELLULAR COMPONENTS</div> <div> Cells consist of several components. Some important and common ones are discussed below:</div> <div> Cell membrane</div> <div> Cell wall</div> <div> Cytoplasm</div> <div> Cytoskeleton</div> <div> Organelles (e.g. nucleus, ribosomes)</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 12</div> <div> A typical animal cell</div> <div> Cell Membrane</div> <div> Cell membrane is the external most layer that covers the cell from outside.</div> <div> Functions of the cell membrane are:</div> <div> o It acts as a barrier, i.e., it separates the cell from environment.</div> <div> o It provides protection to the inner parts of the cells including all the organelles.</div> <div> o Another important function of cell membrane is transport of materials. Cell</div> <div> membrane manages the transport in and out of the cell.</div> <div> Structure of plasma membrane</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 13</div> <div> Structure and Functions of Cell Membrane</div> <div> Structure of cell membrane is described by Fluid Mosaic Modal. It consists of lipid bilayer,</div> <div> proteins and carbohydrates. Lipid bilayer provides it with fluidity, flexibility and transport of</div> <div> lipid like substances. Proteins are integrated inside the membrane or present on its peripheries</div> <div> called integrated proteins and peripheral proteins, respectively. Some proteins are</div> <div> transmembrane, i.e., these are integrated and their ends (domains) are exposed from both</div> <div> intracellular and extracellular side of the membrane. These make channels for transport of</div> <div> materials, e.g., aquaporins are the protein channels for transport of water. Proteins and</div> <div> glycoproteins (carbohydrates attached to proteins) make receptors for message transmission.</div> <div> Cells carry out their message transmission with other cells or environment with the help of</div> <div> these glycoproteins mostly, we call these receptors.</div> <div> Movements across Cell Membrane</div> <div> Some molecules can pass directly e.g. few lipids.</div> <div> Other molecules need channels to pass through; channels are made up of proteins.</div> <div> There are different types of channels for different molecules like water channels and</div> <div> ion channels (Sodium channels, Calcium channels).</div> <div> Cell Wall</div> <div> It is the outermost covering in many organisms surrounding the cell membrane. Prokaryotic</div> <div> cells, fungi and plant cells have a cell wall around their cell membrane. Cell wall makes the</div> <div> outermost covering in these organisms. Cell wall is tough in comparison to cell membrane; it</div> <div> is a rigid structure. Cell wall in plants consists of cellulose, hemicellulose, and pectin.</div> <div> Fungal cell walls consist of a long polymer called, chitin. Prokaryotic cell wall consists of a</div> <div> polymer, called peptidoglycan. Functions of the cell wall are protection, shape, strength and</div> <div> support. Plant cells have 2 types of cell wall, primary cell wall and secondary cell wall.</div> <div> Primary wall consists of mainly cellulose, hemicellulose and pectin. Secondary cell wall</div> <div> contains cellulose and some other molecules like lignin which make it stronger structure.</div> <div> Primary cell wall</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 14</div> <div> Secondary cell wall</div> <div> Cytoplasm</div> <div> Cytoplasm is a semi transparent substance present between plasma membrane and the</div> <div> nucleus. It contains water in which organic (e.g. proteins, carbohydrates) and inorganic</div> <div> materials (e.g. salts), which are partially or fully dissolved in this solution. Cytoplasm</div> <div> provides space for metabolic reactions (e.g. glycolysis). It also provides space for functioning</div> <div> of organelles and metabolic reactions.</div> <div> Cytoskeleton</div> <div> Cytoskeleton is the skeletal framework of the cell – a network of filaments and tubules. There</div> <div> are three types of cytoskeletal elements called microfilaments, intermediate filaments and</div> <div> microtubules.</div> <div> Microfilaments are the smallest in their diameter. These help in movement of organelles and</div> <div> the cell. These consist of helical chains of a protein called actin e.g. in muscle cells these are</div> <div> highly modified. Intermediate filaments are intermediate in size. These consis of different</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 15</div> <div> proteins belong to a protein family called keratins. These filaments help in maintaining shape</div> <div> and placement of the cell and its various parts. These also provide protection to various parts</div> <div> of the cell particularly to the nucleus. Microtubules are largest in diameter, these filaments</div> <div> consist of a protein called tubulin which makes dimers and then long and large hollow tubes.</div> <div> These help in movement of the organelles inside the cells and also in movement of the cell</div> <div> itself. Cilia and flagella consist of microtubules. These filaments help in maintaining shapes</div> <div> of organelles and cell. For example these make the nuclear lamina, a layer that maintain the</div> <div> shape of the nucleus and give it support.</div> <div> Cytoskeletal fibers</div> <div> Cell Organelles</div> <div> These are sub-cellular structures that perform a particular function. These include nucleus,</div> <div> mitochondria, endoplasmic reticulum and many more.</div> <div> Nucleus</div> <div> It is the organelle that contains genetic material. It is present in the center in animal cells</div> <div> usually. In plant cells, it is present on a side due to presence of a large vacuole. Nucleus is</div> <div> covered by nuclear membrane with nuclear pores. It is filled with a fluid called nucleoplasm.</div> <div> It also contains a denser body called nucleolus which is involved in ribosomal RNA</div> <div> production. Genetic material is present inside the nucleus in most of the eukaryotic cells,</div> <div> though, some cells have extranuclear DNA. DNA is present in the form of chromosomes,</div> <div> which are visible during cell division.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 16</div> <div> Ribosomes</div> <div> Ribosomes are the protein making machinery of the cells. These are present free in cytoplasm</div> <div> or attached to endoplasmic reticulum. A large number of ribosomes are present in cells.</div> <div> Eukaryotic ribosomes are slightly different than prokaryotic ones in their size.</div> <div> Structure of a ribosome</div> <div> Mitochondria</div> <div> Mitochondria are called power house of the cell. These make energy for the cells in the form</div> <div> of ATP (Adenosine Tri Phosphate). ATP is the biological or chemical form of energy.</div> <div> Mitochondria have a double membrane, one is called outer and the other is inner membrane.</div> <div> Mitochondria are filled with matrix containing circular DNA molecule and other molecules</div> <div> including the enzymes. Mitochondria are self replicating organelles.</div> <div> Mitochondria</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 17</div> <div> Plastids</div> <div> Plastids are the double membrane bound organelles, present in plants and in the other</div> <div> organisms which are producers such as algae. These are of three main types:</div> <div> o Chloroplasts are present in the green parts of plants. These are green in color</div> <div> and their color is due to chlorophyll, the green pigment. These help in</div> <div> photosynthesis.</div> <div> o Chromoplasts are the organelles present in the fruits and flowers of the plants.</div> <div> Beautiful colors of fruits and flowers are due to presence of Chromoplasts</div> <div> which contain red, yellow, orange and more colored pigments.</div> <div> o Lecuoplasts are the plastids present in the roots and tubers. These are colorless</div> <div> pigments and their function is to store various materials in the roots and</div> <div> tubers, e.g., potatoes.</div> <div> Plastids have a double membrane system. Their membranes are called outer membrane and</div> <div> inner membrane. They have a membrane system called thylakoid. Stacks thylakoids are</div> <div> called grana. They have a matrix inside inner membrane which is called stroma. These</div> <div> organelles like mitochondria have their own circular DNA. These are self replicating</div> <div> organelles.</div> <div> Structure of a chloroplast (a kind of plastid)</div> <div> Endoplasmic Reticulum</div> <div> Endoplasmic reticulum (ER) is a network of interconnected channels present inside the cells.</div> <div> This is of two types: Rough ER and Smooth ER. Rough endoplasmic reticulum is the rough</div> <div> due to the ribosomes present on its surface. This type is involved in protein modification. The</div> <div> other type is free of ribosomes so that shape of this one is smooth giving it its name. SER is</div> <div> involved in metabolism of lipids and carbohydrates.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 18</div> <div> Endoplasmic reticulum and Golgi apparatus</div> <div> Golgi Apparatus</div> <div> This is also called Golgi bodies or Golgi complex. This is also very important organelle of</div> <div> the cells. It was discovered by Camillo Golgi. Golgi apparatus consist of flattened disks</div> <div> called cisternae which are associated with endoplasmic reticulum. These are called the post</div> <div> office of the cell because these pack materials in the form of vesicles. For example the</div> <div> proteins formed by the ribosomes and modified by the endoplasmic reticulum enter in the</div> <div> cisternae and here these are packed in the vesicles and transferred to the part of the cell where</div> <div> these are required or secreted out of cells.</div> <div> Centrioles</div> <div> These are hollow and cylindrical bodies present near the nucleus of the animal cells. It is also</div> <div> present in some lower plants. A pair of Centrioles is collectively called centrosome. Their</div> <div> function is during cell division. These make the spindle fiber during cell division in animal</div> <div> cells.</div> <div> Vacuoles</div> <div> Vacuoles are membrane bound organelles present in most of the cells. Their major function is</div> <div> storage of various materials including food materials to waste materials. If these store food</div> <div> then these are called food vacuoles. Their size is from small to very large in different cells</div> <div> according to the requirements of the cells. In mature plant cells a single large vacuole is</div> <div> present. Contractile vacuole in unicellular fresh water organisms helps in removal of water</div> <div> from the body.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 19</div> <div> Lysosomes</div> <div> Lysosomes are membranous sacs filled with enzymes. Lysosomes are spherical bag like</div> <div> structures that are bound by a single layer membrane. These are found in all eukaryotic cells</div> <div> and act as 'garbage disposal' or the 'digester' of the cell. These act as disposal system of the</div> <div> cell. They break down complex proteins, carbohydrates, lipids and other macromolecules into</div> <div> simpler compounds. These simple compounds are returned to the cytoplasm and are used as</div> <div> new cell building materials. They are used for digestion of cellular waste products, dead cells</div> <div> or extracellular material such as bacteria.</div> <div> Exercise</div> <div> 1. Draw the structure of an animal cell.</div> <div> 2. Draw structure of a plant cell.</div> <div> 3. Compare mitochondria with chloroplast.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 20</div> <div> Biology lecture # 3</div> <div> Diversity of Cells and Mitosis</div> <div> Animal Cell Vs Plant Cell</div> <div> Animal Cell Plant Cell</div> <div> Cell membrane is outer most layer</div> <div> Many small vacuoles</div> <div> Nucleus in the center</div> <div> Roughly round and/or have variable</div> <div> shapes</div> <div> Plastids are absent</div> <div> Cilia present</div> <div> Centrioles present</div> <div> Cell wall is present outside the cell</div> <div> membrane</div> <div> Have a large central vacuole</div> <div> Nucleus on a side</div> <div> Roughly rectangular shape due to</div> <div> presence of cell wall</div> <div> Plastids are present</div> <div> Cilia rarely present</div> <div> Centrioles absent in most of the plants</div> <div> A typical animal cell</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 21</div> <div> A typical plant cell</div> <div> Prokaryotic Cell Vs Eukaryotic Cell</div> <div> Prokaryotic Cells Eukaryotic Cells</div> <div> No defined nucleus but a nucleoid</div> <div> region</div> <div> No membrane bound organelles</div> <div> Small in size (e.g. 1-2 microns in</div> <div> bacteria)</div> <div> Cell wall consist of peptidoglycan (a</div> <div> polymer of amino acids and sugars)</div> <div> Defined nucleus with nuclear</div> <div> membrane</div> <div> Membrane bound organelles are</div> <div> present</div> <div> Larger than prokaryotic cells on</div> <div> average (20 microns of animal cells)</div> <div> Cell wall consist of cellulose</div> <div> (plants) and chitin (fungi)</div> <div> CELL DIVISION</div> <div> Division is the property of cells. Cells have to divide for various purposes, for reproduction</div> <div> or for growth and repair of the tissues. There are two types of the cells called somatic cells</div> <div> and germ line cells. Somatic cells are those which make all the tissues of the body except for</div> <div> some cells which are involved in reproduction. Few cells involved in reproduction and are</div> <div> meant for making gametes for reproduction.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 22</div> <div> There are two types of the cell divisions called Mitosis and Meiosis. Mitosis is the division of</div> <div> the somatic cells and also serves as means of asexual reproduction. Meiosis is however</div> <div> involved in division of the germ line cells.</div> <div> Stages of mitosis in onion root tip cells</div> <div> CELL CYCLE</div> <div> Cells go through a cyclic process in which they pass by various phases over time. These</div> <div> phases include a phase of rest, high metabolic activity and division. It is also defined as the</div> <div> sequence of events or a cyclic process between divisions of the cell. The cell cycle consists of</div> <div> the following phases:</div> <div> o Interphase (consist of Gap 1 phase, Synthesis Phase, Gap 2 phase)</div> <div> o M Phase (Mitosis or Division Phase)</div> <div> o Resting or G0 Phase (Gap 0, read as Gap not)</div> <div> Interphase</div> <div> Interpahse consist of following phases. This is normally called as rest phase but actually it is</div> <div> a phase of high metabolic activity.</div> <div> Gap 1</div> <div> Cells increase in size in Gap 1. They produce materials required for DNA synthesis.</div> <div> The G1 checkpoint control mechanism ensures that everything is ready for DNA synthesis.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 23</div> <div> Synthesis phase</div> <div> DNA replication occurs during this phase. An S phase check point checks that</div> <div> whether the synthesis of DNA is correctly done or not. If everything is correct cell continue</div> <div> to the next phase and if not then cell wither have to die or correct its errors.s</div> <div> Gap 2</div> <div> During the gap between DNA synthesis and mitosis, the cell will continue to grow.</div> <div> Cell prepares all the materials required for division, e.g. microtubule proteins. The</div> <div> G2 checkpoint control mechanism ensures that everything is ready to enter the M (mitosis)</div> <div> phase and divide.</div> <div> Cell Division or M- Mitosis Phase</div> <div> Cell growth stops at this stage and cellular energy is focused on the orderly division into two</div> <div> daughter cells. A checkpoint in the middle of mitosis (called Metaphase Checkpoint) ensures</div> <div> that the cell is ready to complete cell division.</div> <div> Resting or G0 (Gap 0)</div> <div> A resting phase in which the cell has leaves the cycle and has stopped dividing. G0 starts</div> <div> from G1 and cell may sustain in G0 may be for years.</div> <div> Mitosis</div> <div> Mitosis is the cell division that results in two daughter cells which are like each other.</div> <div> Though, mitosis is a term that is used to describe the nuclear division.</div> <div> Cell division consists of following phases:</div> <div> Karyokineses – division of nucleus</div> <div> o Divided into Prophase, Metaphase, Anaphase and Telophase</div> <div> Cytokinesis – division of cell</div> <div> o Different in animal and plant cells</div> <div> Karyokinesis</div> <div> 1. Prophase</div> <div> o Chromatin material condenses and chromosomes becomes visible</div> <div> o Each chromosome is replicated (duplicated) and consist of two sister</div> <div> chromatids</div> <div> o At the end of the stage nuclear membrane disappear</div> <div> o Centrioles move towards poles of the cell and microtubules starts forming</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 24</div> <div> 2. Metaphase</div> <div> o Chromosomes arrange themselves at the equator</div> <div> o Kinetochores are attached to the microtubules</div> <div> 3. Anaphase</div> <div> o Chromosomes starts moving towards the poles</div> <div> o The sister chromatids separate from each other, so each sister chromatid move</div> <div> towards a pole</div> <div> 4. Telophase</div> <div> o Chromosomes (sister chromatids) reaches at the poles</div> <div> o Nuclear material starts de-condensing again</div> <div> o Nuclear membrane starts forming</div> <div> The nuclear division is complete, next is the Cytokinesis or division of the cell.</div> <div> Anaphase</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 25</div> <div> Cytokinesis</div> <div> Cytokinesis in plant and animal cells is different from each other. In plant cells, a cell plate</div> <div> starts forming in the center of the cell and moves towards sides. The cell plate divides the cell</div> <div> into two cells. The cell plate consists of material produced by Golgi bodies in vesicles. This</div> <div> material contains the cell membrane and cell wall components.</div> <div> Cytokinesis in animal cells occurs in a different way. In animal cells a cleavage furrow is</div> <div> formed by invagination of cell membrane. This process occur with the help of cytoskeleton</div> <div> (microfilaments particularly). The furrows divide the cell into 2 daughter cells.</div> <div> Cleavage in animal cells</div> <div> Importance of Mitosis</div> <div> Mitosis is the cell division which helps in development and growth processes of the cells and</div> <div> hence the tissues. Development of new cells is a requirement in many parts of the body like</div> <div> epithelia usually keep growing. Replacement of cells and wound healing is another</div> <div> requirement of the organisms which also need new cells. Regeneration is a capability of some</div> <div> Telophase</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 26</div> <div> organisms. They came make their lost parts. This process also needs mitosis. Mitosis also</div> <div> serves as a means of asexual reproduction in various organisms.</div> <div> Errors in Mitosis</div> <div> Cells divide correctly most of the times because of many check points at various phases but</div> <div> sometimes it may go wrong. If it happens due to any reason the result is usually serious</div> <div> problems. Uncontrolled division of the cells may result into abnormal tissue growth and</div> <div> cancer.</div> <div> Exercise</div> <div> 1. Draw various steps of mitosis.</div> <div> 2. Demonstrate the process of cytokinesis in animal cells.</div> <div> 3. Give any two examples of regeneration in animals.</div> <div> 4. Show the process of cytokinesis in plant cells with the help of a diagram.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 27</div> <div> Biology lecture # 4</div> <div> CELL DIVISION – MEIOSIS</div> <div> Reduction Division</div> <div> MEIOSIS - CONSIST OF TWO DIVISIONS</div> <div> Meiosis occur in germ line cells to make gametes, gametes are formed for sexual</div> <div> reproduction. Meiosis is also called reduction division because it results in four daughter cells</div> <div> which are haploid. We know that chromosomes occur in pairs e.g. human have 46</div> <div> chromosomes in 23 pairs which is called a diploid number. The chromosomes in each pair are</div> <div> called homologous because these are like each other and are complementary to each other.</div> <div> Meiosis makes cells that have a half number of the chromosomes in each daughter cell called</div> <div> a haploid number also.</div> <div> Diploidy and Polyploidy</div> <div> The condition of having two sets of chromosomes is called diploidy (2N number of</div> <div> chromosomes). The gametes formed by meiosis, hence, are called haploid (N number of</div> <div> chromosomes). For example, in humans 2N is 46 and N is 23 in each gamete, when gametes</div> <div> combine in fertilization the chromosome number is retained to 2N. Some plants have more</div> <div> than two sets of chromosomes and are called polyploids. This characteristic is called</div> <div> polyploidy.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 28</div> <div> Phases of Meiosis</div> <div> • Meiosis I</div> <div> o The reduction division</div> <div> o Chromosome number becomes half in each daughter cell (N)</div> <div> • Cytokinesis I</div> <div> • Meiosis II</div> <div> o Just like mitosis</div> <div> o Chromosome number remains same in daughter cells</div> <div> • Cytokinesis II</div> <div> Meiosis I</div> <div> • Meiosis I consist of following phases:</div> <div> o Prophase I</div> <div> o Metaphase I</div> <div> o Anaphase I</div> <div> o Telophase I</div> <div> Stages of Meiosis I</div> <div> • Prophase I is a long phase in meiosis. It consist of following stages:</div> <div> o It is marked by the pairing of homologous chromosomes (synapses) and</div> <div> recombination (exchange of the parts of chromosomes.</div> <div> o Paired chromosomes are called Bivalents or Tetrads.</div> <div> Homologous chromosomes carry out recombination during meiosis.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 29</div> <div> • Metaphase I</div> <div> o Chromosomes attach to the spindle fibers by kinetochore, one kinetochore per</div> <div> a chromosome and not per chromatid.</div> <div> o One homologue on each side so there is a 50-50 chance to get each parents</div> <div> chromosome.</div> <div> • Anaphase I</div> <div> o The chromosomes move towards the poles.</div> <div> o A homologue, consist of two chromatids moves and sister chromatids do not</div> <div> separate.</div> <div> o The result is half number of chromosomes towards each pole.</div> <div> • Telophase I and Cytokinesis</div> <div> o Chromosomes reach at poles, half on each side.</div> <div> o Cell divides and then starts meiosis II.</div> <div> Events of Meiosis II</div> <div> • Karyokinesis</div> <div> o Prophase II</div> <div> o Metaphase II</div> <div> o Anaphase II</div> <div> o Telophase II</div> <div> • Cytokinesis</div> <div> o Each cell divides into two cells.</div> <div> At the end of meiosis each cell divides into 4 haploid cells.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 30</div> <div> This division is different in males and females.</div> <div> In females, after first meiotic division (meiosis I), cytoplasm is unequally distributed and one</div> <div> large and other small cell are produced. The small cell is called a polar body. Then both of</div> <div> these cells carry out meiosis II. Polar body divides into 2 polar bodies. The large cell however</div> <div> is divided into one ovum (large) and another polar body. So that meiosis results into 1 ovum</div> <div> and 3 polar bodies.</div> <div> In males, both meiotic divisions results into equal sized cells called sperms.</div> <div> Comparison of Mitosis and Meiosis</div> <div> Mitosis Meiosis</div> <div> • Cell divides into 2 daughter cells</div> <div> • Alike in males and females</div> <div> • Chromosome number remains equal</div> <div> (2N) in daughter cells</div> <div> • One cell divides into 4 daughter cells</div> <div> • Different in males and females</div> <div> • Chromosome number becomes half</div> <div> (N) in daughter cells</div> <div> Importance of Meiosis</div> <div> Major advantage of meiosis is the genetic variations by recombination (crossing over).</div> <div> During prophase I of the meiosis crossing over takes place which result in genetic</div> <div> recombination. When gametes combine to make a zygote, more variations arise. This</div> <div> variation assures new combinations resulting in increase in adaptability of the organism.</div> <div> Errors in Meiosis</div> <div> Meiosis is a well regulated process but sometimes errors may arise which may lead to mostly</div> <div> serious disorders. The common cause of disorders in non-disjunction of the homologous pairs</div> <div> of chromosome abnormally. This may results into unequally distributed chromosomes in the</div> <div> gametes and when these fertilize, they give rise to individuals with disorders.</div> <div> For example, in Down’s syndrome the affected individual have 3 homologues in the 21st pair</div> <div> of chromosomes.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 31</div> <div> Non-disjunction results into abnormal gametes, e.g., in above diagram N and N are normal</div> <div> and N +1 or N -1 are abnormal gemetes</div> <div> Twins</div> <div> There are two types of twins.</div> <div> • Fraternal twins</div> <div> o These are produced by separate eggs (also called dizygotic twins)/ These are</div> <div> produced if two eggs are released and fertilized.</div> <div> o These are genetically different from each other and may be both males,</div> <div> females or both male and female.</div> <div> • Identical twins</div> <div> o These are produced by division in the same egg (also called monozygotic</div> <div> twins). These are produced by division in the zygote.</div> <div> o These are genetically same / identical and have same characteristics. Both of</div> <div> these are either males or females.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 32</div> <div> Environment and twins</div> <div> Environment may affect even the identical twins. Identical twins may also have different</div> <div> characteristics if they are brought up in different environments. We know that the genes</div> <div> interact with environment to produce various characteristics. This characteristic also affects</div> <div> the twins.</div> <div> Exercise</div> <div> 1. Draw various steps of meiosis I.</div> <div> 2. Demonstrate difference between the meiosis in females and males.</div> <div> 3. What are the effects of non-disjunction? Describe with the help of a diagram.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 33</div> <div> Biology lecture # 5</div> <div> Chromosomes, DNA and Genes</div> <div> Heredity Information Flow</div> <div> Reproducing itself is a property of life. Transferring characteristics to next generation is a</div> <div> property of living organisms. Heredity information flow in living organisms is carried out by</div> <div> the genes. The “Chromosome theory of heredity” states that the genes are present on</div> <div> chromosomes and are responsible for the transfer of characteristics from generation to</div> <div> generation. Genes are present in the form of DNA molecules, organized in a structure called</div> <div> chromosome (chromatin material).</div> <div> Chromatin - the Genetic Material</div> <div> Genetic material is present in the nucleus of the cell in eukaryotes and in the nucleoid region</div> <div> in prokaryotes. These are called chromatin material. Chromatin material is not visible during</div> <div> interphase (non-dividing state) of the cell. These become visible during cell division due to</div> <div> condensation of chromosomes.</div> <div> Functions of Genetic Material</div> <div> There are some important properties of genetic material, which are following:</div> <div> · It replicates itself.</div> <div> • It regulates the growth and development of the organism.</div> <div> • It allows the organism to adapt to the environmental changes.</div> <div> Chromosomes - DNA – Genes</div> <div> Chromosomes consist of DNA molecule associated with proteins. In chromosomes, DNA is</div> <div> wrapped around proteins. Few of these proteins are called histones and few others. DNA is</div> <div> associated with histone and non-histone proteins in a chromosome.</div> <div> Introduction of DNA and Gene</div> <div> DNA is a macromolecule (large molecule) organized in structure chromosome. In</div> <div> prokaryotes DNA is a circular molecule. In eukaryotes it is a long linear molecule.</div> <div> Mitochondria and chloroplast also have their own circular DNA molecules.</div> <div> Gene is a length of DNA that codes for a peptide or protein. So that gene is a part or length of</div> <div> DNA.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 34</div> <div> Condensation of Genetic Material</div> <div> Chromatin material condenses during prophase of mitosis in the form of chromosomes.</div> <div> Chemical analysis shows that chromosome consist of DNA and proteins. DNA is a long</div> <div> molecule about 2nm thick running continuously within each chromosome. Chemical analysis</div> <div> shows that DNA is acidic in nature.</div> <div> The Structure of Chromosomes</div> <div> Chromosome consists of a DNA molecule wound around proteins. DNA in human cell (all</div> <div> chromosomes) is about 6 feet long, packed in a microscopic nucleus of a cell. In one human</div> <div> chromosome, it is 1.7-8.5 cm long. How is this possible? The answer is “coiling” and “supercoiling”.</div> <div> The chromosome consists of highly condensed structure. If we can open this like a</div> <div> thread, then the long thread will appear like a flower like structure called solenoid which</div> <div> consists of many smaller units. These small units are called “nucleosomes”. A nucleosome is</div> <div> a length of DNA coiled around a set of proteins. The DNA coils around histones twice, which</div> <div> is up to 200 base pairs long. Two nucleosomes are connected to each other by a length of</div> <div> DNA, which is called “linker DNA” (up to 80 base pairs long).</div> <div> Chromosome coiling and nucleosome</div> <div> Two nucleosomes</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 35</div> <div> Chemical Composition of DNA</div> <div> DNA is a complex macromolecule (large molecule). DNA stands for Deoxyribose Nucleic</div> <div> Acid. The smallest unit of DNA is called a “nucleotide”; nucleotides join to make</div> <div> polynucleotide. We can say that DNA consists of nucleotides joined together.</div> <div> Nucleotides</div> <div> Each nucleotide consists of:</div> <div> 1. Deoxyribose sugar</div> <div> 2. Phosphate group</div> <div> 3. Nitrogenous base</div> <div> Structure of a nucleotide</div> <div> There are four nucleotides based upon four different nitrogenous bases attached to them.</div> <div> Nitrogenous bases are of two types: purines and pyrimidine. Purines include two bases</div> <div> Adenine and Guanine which have a double ringed structure. Pyrimidine bases include the</div> <div> other ones called Thymine and Cytosine that have single ringed structure.</div> <div> Mechanism of Gene Action</div> <div> Genes express themselves by making proteins. Making the proteins by DNA occur by two</div> <div> processes called transcription and translation. Transcription is formation of a form of RNA</div> <div> from DNA called messenger RNA (mRNA). mRNA is formed inside the nucleus in</div> <div> eukaryotes and in nucleoid region in prokaryotes. The next process is translation, which is</div> <div> formation of a protein or peptide by mRNA with the help of another organelle called</div> <div> ribosome.</div> <div> Replication is another function of DNA. It is doubling of DNA molecule to make two copies</div> <div> of itself. Replication occurs before cell division to make copies of DNA for the daughter</div> <div> cells.</div> <div> Genetic code is a term used for the parts of DNA that code for proteins. A codon is a 3</div> <div> nucleotides code for an amino acid, i.e., codon is a 3 nucleotide set of DNA molecule that</div> <div> codes for a protein.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 36</div> <div> Transcription and Translation</div> <div> • Transcription = DNA mRNA</div> <div> • Translation = mRNA Protein</div> <div> • The following scheme is called the central dogma of molecular biology / genetics</div> <div> DNA RNA Protein</div> <div> Transcription</div> <div> • DNA mRNA</div> <div> The process of transcription involves an enzyme called RNA polymerase. One strand of DNA</div> <div> act as the template strand which is actually coded into the mRNA.</div> <div> • Steps of transcription</div> <div> o RNA polymerase identifies and attaches to a region called promoter on the</div> <div> DNA upstream the gene.</div> <div> o RNA polymerase open the double helix chain which results in the formation of</div> <div> transcription bubble.</div> <div> Transcription Process</div> <div> • RNA polymerase moves on the gene, the helix unwinds and make a</div> <div> complementary strand of RNA. This strand of mRNA protrudes out of</div> <div> transcription bubble.</div> <div> • At end of the gene there is a stop sequence. Usually it is a series of GC base</div> <div> pairs followed by a series of AT base pairs.</div> <div> • These sequences make a hair pin loop like structure which stops RNA</div> <div> polymerase from transcribing.</div> <div> • Thymine is coded as uracil in mRNA.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 37</div> <div> Transcription in Prokaryotes and Eukaryotes</div> <div> In prokaryotes, the mRNA directly moves into cytoplasm and its translation starts because</div> <div> there is no nuclear membrane, nucleoid region is continuous with cytoplasm. In eukaryotes,</div> <div> mRNA formed moves out of nucleus through nuclear pores and then it is translated in the</div> <div> cytoplasm with the help of ribosomes.</div> <div> Modification of mRNA in eukaryotes</div> <div> mRNA in eukaryotes has to travel from nucleus to cytoplasm, to protect it from the action of</div> <div> nucleases (the DNA cutting enzymes) and proteases (protein cutting enzymes), it is modified.</div> <div> On its 5’ end a cap of 7 methyl GTP is added; while on the 3’ end a poly A tail is added.</div> <div> Introns are also removed. Introns are DNA sequences in the eukaryotes which are non coding</div> <div> and should be removed from the mRNA. The coding regions are called exons.</div> <div> mRNA in eukaryotes have regions – exons and introns</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 38</div> <div> Translation</div> <div> • mRNA ------- Protein</div> <div> The process of translation consists of three major steps: initiation, elongation, and</div> <div> termination.</div> <div> Steps of Transcription</div> <div> • In prokaryotes, translation starts while transcription is going on because there is no</div> <div> barrier between nucleoid and cytoplasm.</div> <div> • In eukaryote, first introns are removed.</div> <div> Process of Translation</div> <div> Initiation:</div> <div> • The mRNA binds to the small unit of ribosome.</div> <div> • The large ribosomal subunit has 3 binding sites called E (Exit), P (Peptidyl), and A</div> <div> (Aminocyl).</div> <div> • When the first codon (triplet code) is aligned at the P site then the large ribosomal</div> <div> subunit attaches to the small subunit.</div> <div> A ribosome</div> <div> • A tRNA carrying the amino acid methionine attaches to the start codon (AUG) on the</div> <div> messenger RNA.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 39</div> <div> A tRNA with an amino acid on the P site</div> <div> Elongation:</div> <div> • A tRNA with its amino acid attaches to the A binding site.</div> <div> • Peptide bond formation occurs between the methionine and the amino acid carried at</div> <div> the A binding site.</div> <div> • Ribosome moves in the 3' direction down the messenger RNA by three bases, shifting</div> <div> the tRNA and polypeptide chain to the P Binding site.</div> <div> • The A binding site is open and a vacant tRNA (without amino acid) is in the E</div> <div> binding site.</div> <div> • Now, the next tRNA brings another amino acid and bind to A site.</div> <div> • A peptide bond is formed between the second and this new (thirs) amino acid.</div> <div> • Ribosome moves in 3’ direction and the vacant tRNA is released from the E site.</div> <div> • This process continues until a stop codon arrives on mRNA.</div> <div> • A Releasing factor comes and binds to the A site in place of stop codon. The</div> <div> polypeptide chain separates from tRNA and ribosome. Then ribosomal units</div> <div> disassemble again. mRNA molecule also released which has been coded.</div> <div> Peptide bond is formed between the amino acids brought by tRNAs present on P and A</div> <div> sites.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 40</div> <div> Growing polypeptide is present on P site and empty amino acid on E site. New tRNA</div> <div> with an amino acid will come and attach on A site.</div> <div> Exercise</div> <div> 1. Explain the process of transcription with the help of diagram.</div> <div> 2. Explain the process of translation with the help of diagrams.</div> <div> 3. Differentiate between the transcription and translation processes of prokaryotes and</div> <div> eukaryotes.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 41</div> <div> Biology lecture # 6</div> <div> DIGESTIVE SYSTEM</div> <div> Nutrition</div> <div> Acquiring energy from environment is one essential property of life. Plants acquire energy</div> <div> from sunlight and prepare their food. We call them producers. Animals, however, acquire</div> <div> energy from either plants or other animals or organic materials. We call the consumers or</div> <div> decomposers.</div> <div> Common Modes of Nutrition in Animals</div> <div> Herbivores</div> <div> ◦ Plant eaters, e.g. goat</div> <div> Carnivores</div> <div> ◦ Flesh, meat eaters, e.g. lion</div> <div> Omnivores</div> <div> ◦ Mixed food, e.g., bear, crows</div> <div> Detritivores</div> <div> ◦ Dead organic matter, e.g. earthworms</div> <div> Dentition is according to the mode of nutrition</div> <div> Dentition in animals; incisor, canine, premolar and molar teeth</div> <div> Mouth Parts also are also according to the mode of nutrition</div> <div> Animals have different types of tongues according to their mode of nutrition. For example,</div> <div> frogs have forked, inverted and sticky tongue to catch insects. Tongue of chameleon is also</div> <div> sticky and very long. Beaks of birds make another example. Birds have a variety of beaks;</div> <div> long, small, curves and many other. All of these are present in birds according to their mode</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 42</div> <div> of nutrition for example parrots have long curves beak for cutting and breaking nuts. Pelican</div> <div> have a very long and wide for catching fish from water. Snouts in mammals make another</div> <div> example. Mammals have different snouts according to their food.</div> <div> A parrot: observe the long and curved beak.</div> <div> Nutrition, Ingestion, Digestion, Absorption, Assimilation, Elimination</div> <div> After acquiring food and ingestion, animals have to digest it.</div> <div> Digestion is actually, breaking down food into small ingredients. For example,</div> <div> carbohydrates to glucose.</div> <div> Absorption is movement of food into blood after digestion.</div> <div> Assimilation is utilizing those broken small molecules for getting energy for</div> <div> organisms functions.</div> <div> Elimination is removal of the undigested matter from the body.</div> <div> Nutrition and Digestion in Human beings</div> <div> Humans are omnivores, i.e., we eat plants (vegetables) and meat (chicken, beef). Digestive</div> <div> system of humans hence is adapted accordingly.</div> <div> Basic Components of Human Digestive System</div> <div> Alimentary canal</div> <div> o From mouth to anus</div> <div> Alimentary canal in humans consist of following parts:</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 43</div> <div> o Oral cavity</div> <div> o Pharynx</div> <div> o Esophagus</div> <div> o Stomach</div> <div> o Intestine (small and large)</div> <div> Rectum and anus</div> <div> Accessory glands</div> <div> o Liver, Pancreas</div> <div> Digestive system in human beings</div> <div> Sensing the Food</div> <div> We look at the food and smell when we get a food. These are called sensory qualities of food.</div> <div> This is the first part of food selection and foods which are improper are rejected. If the food</div> <div> looks inappropriate or it smells bad, it is rejected. This is a human adaptation just like other</div> <div> animals.</div> <div> Alimentary Canal - From mouth to anus</div> <div> The Oral Cavity</div> <div> Food selection is one function of the oral cavity. Oral cavity has tongue with taste buds. Food</div> <div> selection takes place by taste buds if food tastes bad it is rejected. Tongue converts the</div> <div> ground food mass to a bolus. Grinding the food is the other important function of oral cavity.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 44</div> <div> Oral cavity contains teeth for this purpose. Dentition is according the food types. Teeth are</div> <div> of four types; incisors, canine, premolars and molars. Human have all four types of teeth; few</div> <div> animals have others. Lubrication and chemical digestion is another function of the oral</div> <div> cavity. Salivary glands secrete saliva which contains amylase for digestion of starch. It also</div> <div> contains mucous for lubrication of food.</div> <div> Pharynx</div> <div> Pharynx is a part of digestive system. It lies just behind the mouth and nasal cavity and above</div> <div> the esophagous and larynx. Food bolus passes through pharynx to enter the esophagus.</div> <div> Pharynx helps swallowing by closing the trachea and nasal cavity pathways.</div> <div> Esophagus</div> <div> It is a long tube starts from pharynx and enters stomach. From pharynx, food enters</div> <div> esophagus. In esophagus, food moves down to stomach by a series of muscular contractions</div> <div> called “peristalsis”. Bolus moves down by alternate contraction and relaxation of muscles of</div> <div> esophagus. Sometimes an antiparistalsis occur, i.e., movement from stomach to mouth that</div> <div> result in vomiting.</div> <div> Stomach</div> <div> Stomach is mainly a storage organ. It also helps in digestion of proteins. Stomach has</div> <div> guarded openings on either side. There is a sphincter (group of muscles) which is pyloric</div> <div> sphincter that controls movement of food from stomach to intestine. The other sphincter is</div> <div> present where esophagus meets stomach. Gastric glands in stomach produces gastric juice,</div> <div> which contain mucus, hydrochloric acid and an enzyme called pepsinogen. Pepsinogen is</div> <div> converted into pepsin which is its activated form. Pepsin converts proteins to peptides.</div> <div> Protection of the stomach walls from the acid particularly is important, mucus secreted by the</div> <div> stomach walls cover the stomach lining to protect it from acidic damage.</div> <div> Stomach is also designed to mix up the food with enzymes and acid. Churning movements of</div> <div> stomach walls thoroughly mixes the food with gastric juice. Churning converts food to</div> <div> chyme, small part of which enters the small intestine by pyloric sphincter.</div> <div> Small Intestine</div> <div> It consist of three parts; duodenum, jejunum and ilium. Duodenum (first 25 cm of intestine) is</div> <div> the first part where most of the digestion occurs. Bile enter here from liver and helps</div> <div> emulsification and digestion of lipids. Pancreatic juice from pancreas also enters here, which</div> <div> contains trypsin, pancreatic amaylase and lipase fordigestion of protein, carbohydrates and</div> <div> lipids. Intestinal juice is also released, which help in digestion of all foods.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 45</div> <div> Jejunum is the next 2.4 m of the small intestine; remaining digestion takes place here. Ilium is</div> <div> the last 3.5 m long part where absorption takes place. Its lumen is highly folded. It have</div> <div> extensions of the epithelium called villi and microvilli, which increases the surface area to a</div> <div> greater extent to increase absorption.</div> <div> A single villus in smalle intestine</div> <div> Large Intestine</div> <div> Undigested food comes in the large intestine. It consists of various parts including caecum,</div> <div> colon, and rectum. Absorption of water from the undigested matter occurs in colon. Water is</div> <div> returned to blood vascular system. Remaining semi solid mass is called feces that are are</div> <div> stored in rectum, when rectum is full it give rise to a reflex for defecation and feces are</div> <div> excreted out.</div> <div> Intestinal Motility is an important factor. If the motility in large intestine is increased then</div> <div> there is less water reabsorption and result is a situation called diarrhea. On the other hand if</div> <div> motility is decreased then constipation is the result which means that feces will have less</div> <div> than normal water.</div> <div> Liver and Pancreas</div> <div> Liver produces a secretion called bile which helps in fat digestion and emulsification. Bile is</div> <div> stored in gall bladder and is released by its contraction. Liver perform various functions</div> <div> called deamination, converting ammonia to urea, destroys old blood cells and manufactures</div> <div> fibrinogen, which is blood clotting factor.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 46</div> <div> Exercise</div> <div> 1. Diagrammatically show various parts of human digestive system.</div> <div> 2. How human beings find out the quality of foods?</div> <div> 3. List various functions of small intestine.</div> <div> 4. List various functions of liver and pancreas.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 47</div> <div> Biology lecture # 7</div> <div> Transport System and</div> <div> Blood – the Circulatory Fluid</div> <div> Why transport systems?</div> <div> Organisms have to exchange materials with the environment. They also need to distribute</div> <div> nutrients, gases and metabolic products within their body.</div> <div> Living organisms …</div> <div> · acquire energy or food from the environment; they have to distribute energy and food</div> <div> within the body.</div> <div> · need an intake of oxygen and removal of carbon dioxide from their bodies.</div> <div> · need to remove toxic materials and waste products from their bodies.</div> <div> · have to distribute hormones and other materials in the body.</div> <div> · have to exchange materials with the environment</div> <div> For all that, they require a Transport System.</div> <div> [</div> <div> Transport systems in organisms</div> <div> A transport system should fulfill the requirements of the organism for all of the above</div> <div> functions like nutrient distribution or gas exchange.</div> <div> We take some examples here:</div> <div> Unicellular organisms</div> <div> ◦ e.g. amoeba</div> <div> Simple multicellular organisms</div> <div> ◦ Small organisms; e.g. sponges, hydra</div> <div> Plants and animals</div> <div> ◦ Plants</div> <div> ◦ Animals</div> <div> Unicellular organisms</div> <div> Unicellular organisms have a simple body, just one cell. Their requirements are also few. For</div> <div> example amoeba performs the transport via cytoplasmic streaming which is the movement of</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 48</div> <div> their cytoplasm and few organelles. Food vacuoles distribute the food in the body. Contractile</div> <div> vacuoles removes the water fro the body. Cytoskeleton helps in the movement of all the</div> <div> above parts.</div> <div> Amoeba</div> <div> Simple multicellular organisms</div> <div> Simple multicellular organisms transport materials by simple methods. Like hydra have a</div> <div> mouth and a body cavity; water enters through mouth and transport of materials takes place</div> <div> in the body cavity. Body wall also exchange materials with the water outside as organism is</div> <div> aquatic. Hence, water act as a medium of transport. Few cells help in transport, which are</div> <div> present inside the body towards body cavity.</div> <div> Hydra: transport system.</div> <div> Transport in plants</div> <div> Transport in plants occurs by roots and conducting tissues called phloem and xylem. Roots</div> <div> absorb water and materials from soil. Plants remove water through a process of transpiration.</div> <div> The leave has guarded openings called stomata, which open and close to remove water.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 49</div> <div> Stomata: opened and closed.</div> <div> [</div> <div> Transport in animals</div> <div> Animals have a system called circulatory system for transport. There are two kinds of this</div> <div> system called an open circulatory system and closed circulatory system. In an open</div> <div> circulatory system, the circulatory fluid is freely moving in the body cavity bathing tissues</div> <div> and there is/are pumping heart/s but these only send blood to some vessels which are then</div> <div> connected to body cavity. In closed circulatory system, the blood never leaves vessels and</div> <div> heart and is always present inside the vessels.</div> <div> Diagrammatic presentation of an open circulatory system. In this system circulatory</div> <div> fluid (e.g. Hemolymph moves into body cavity and from here to back to heart</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 50</div> <div> Diagrammatic presentation of closed circulatory system. I this system, blood never</div> <div> leaves vessels</div> <div> Basic components of human circulatory system</div> <div> Blood is the circulatory fluid which is the medium for transport. Blood vessels are the tubular</div> <div> system for transport of blood within the body. Heart is the pumping organ that pumps the</div> <div> blood toward the body.</div> <div> Composition of blood</div> <div> Human blood consists of plasma (fluid) and cellular content (cells). Plasma is the fluid with</div> <div> dissolved and un-dissolved materials. It consists mainly of water, which have many inorganic</div> <div> and organic materials dissolved in it. Cellular content consist of Red Blood Cells (RBCs),</div> <div> White Blood Cells (WBCs) and Platelets. Red blood cells are also called erythrocytes and</div> <div> white blood cells are also called leukocytes. Plasma consists of 55% of the blood. Cells</div> <div> constitute 45% of the blood Average human body has about 5liters of blood.</div> <div> Blood contents could be separated based upon their densities and weights by various methods</div> <div> including centrifugation and sedimentation.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 51</div> <div> Components of blood</div> <div> Functions of the main components of blood</div> <div> Blood plasma</div> <div> Plasma consist of 55% of the blood, It consist of 92% water. 0.9% of it consists of salts –</div> <div> NaCl, Mg, Zn ions etc. The salts maintain the pH of the blood. Plasma has 7-9% part consist</div> <div> of proteins. Important proteins include antibodies, fibrinogen and albumin. Plasma also</div> <div> contains digested food, nitrogenous wastes, hormones, respiratory gases etc.</div> <div> Blood cells and cell-like bodies</div> <div> Cellular components of blood consist of erythrocytes, leucocytes, thrombocytes. Erythrocytes</div> <div> – Red Blood Cells carry oxygen with the help of a protein called haemoglobin. In men 5-5.5</div> <div> million cells/mm3 RBCs are present. This number is 4- 4.5 million/mm3 in women. Men have</div> <div> usually larger bodies and more muscle mass, so that heir demand for oxygen is more than</div> <div> women.</div> <div> Leukocytes – White Blood Cells are categorized in to two kinds: Agranulocytes and</div> <div> granulocytes.</div> <div> Agranulocytes are theose white blood cells which have nongranulated cytoplasm, these</div> <div> include monocytes and lymphocytes. Granulocytes are those WBCs, which have granulated</div> <div> cytoplasm. These include basophils, eosinophils and neutrophils. Platelets are the third type</div> <div> of cells or we can call these, cell like bodies. These are formed by fragmentation of a single</div> <div> cell called megakaryocyte.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 52</div> <div> Erythrocytes (RBCs) do not have a nucleus at maturity. That is why these look concave</div> <div> under microscope.</div> <div> Blood cells include RBCs and WBCs (lymphocytes, monocytes, neutrophils, eosinophils,</div> <div> and basophils).</div> <div> Platelets</div> <div> Blood groups in human beings and blood transfusion</div> <div> Blood cells have some specific protein present on their surfaces called antigens, which are</div> <div> meant for the identification of the blood cells. About 29 blood groups are identified. The</div> <div> most important blood group systems are, however, two named as ABO and Rh blood group</div> <div> systems. There are four main types of blood groups present in human beings according to</div> <div> ABO blood group system. These blood groups are based upon presence or absence of two</div> <div> antigens on surface of RBCs called antigen A and antigen B (Table 1). Other important blood</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 53</div> <div> group is based upon presence or absence of Rh antigens on the surface of RBCs. The people</div> <div> have Rh antigen on the surface of their RBCs are called Rh positive and those who do not</div> <div> have it are called Rh negative. ABO system works with the help of Rh system. So that we</div> <div> talk of the blood groups based upon ABO system with Rh positive or negative. For example,</div> <div> A +ive means that the person have an A blood type with Rh antigens present.</div> <div> Table 1: Blood groups, antigens and antibodies</div> <div> Blood Group Antigen A Antigen B Antibody A Antibody B</div> <div> A Present Absent Absent Present</div> <div> B Absent Present Present Absent</div> <div> AB Present Present Absent Absent</div> <div> O Absent Absent Present Present</div> <div> Blood transfusion</div> <div> Blood transfusion is required in case of some diseases, surgery or in case of injuries. Blood</div> <div> groups of donor and recipient should match, otherwise could cause agglutination reactions</div> <div> leading to even death of the patient. Blood groups are matched using antigen antibody</div> <div> reactions. A blood group O -ive is called Universal donor because it has not antigens, hence,</div> <div> it cannot react with any of the antibodies in recipient’s blood. Universal acceptor is AB+</div> <div> blood group which has all antigens.</div> <div> Exercise</div> <div> 1. What are the ABO blood groups and how these are important in transfusion?</div> <div> 2. Describe various transportation systems in unicellular and small multicelluar</div> <div> organisms with the help of diagrams.</div> <div> 3. What are various components of blood and how can we separate them?</div> <div> 4. Describe important functions of white blood cells.</div> <div> 5. Identify the following:</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 54</div> <div> Diagrams of blood cells</div> <div> a.</div> <div> ____________________</div> <div> _</div> <div> b. _______________ c.</div> <div> _______________</div> <div> d.</div> <div> _______________</div> <div> e.</div> <div> ____________________</div> <div> f.</div> <div> _________________</div> <div> _</div> <div> g.</div> <div> _______________</div> <div> 6. List various functions of red blood cells.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 55</div> <div> Biology lecture # 8</div> <div> Circulatory System</div> <div> in Humans - Blood Vessels and Heart</div> <div> Circulatory System in Humans</div> <div> Circulatory system in humans consists of blood, vessels and heart. Blood is the circulatory</div> <div> fluid. We can call it a liquid tissue. Blood consist of plasma – the watery fluid and cells – the</div> <div> cellular content. Blood has been described in detail in last lecture. Here we talk about heart</div> <div> and blood vessels. Heart is a pumping organ and is highly muscular. Function of the heart is</div> <div> to pump blood with pressure towards lungs and body. Vessels are of three main types;</div> <div> arteries, veins and capillaries. Arteries carry blood from the heart to body. Veins return blood</div> <div> from body to heart. Capillaries connect arteries to veins. Function of the capillaries is the</div> <div> exchange of materials.</div> <div> Structure and functions of blood vessels</div> <div> Arteries and veins are elastic in their structure. These also have a layers of muscles. These</div> <div> consist of 3 layers:</div> <div> ◦ External layer - connective tissues layer</div> <div> ◦ Middle layer, consist of smooth muscles</div> <div> ◦ Inner layer, consist of endothelium</div> <div> Lumen of both of these is meant for blood flow. Arteries have a lumen smaller in diameter</div> <div> and veins have large.</div> <div> Artery, vein and capillaries</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 56</div> <div> Comparison of Arteries, Veins and Capillaries</div> <div> Arteries Veins Capillaries</div> <div> Carries</div> <div> blood</div> <div> From heart to body;</div> <div> one exception</div> <div> pulmonary artery</div> <div> From body to heart;</div> <div> one exception is</div> <div> pulmonary vein</div> <div> From arteries to</div> <div> tissues to veins</div> <div> Stat of</div> <div> blood</div> <div> Oxygenated Deoxygenated Oxygenated to</div> <div> deoxygenated</div> <div> Layers 3 3 1</div> <div> Walls Thick Thin in comparison to</div> <div> arteries</div> <div> Very thin; one cell</div> <div> thick only called</div> <div> endothelium</div> <div> Pressure High Low Medium</div> <div> Valves Absent Present Absent</div> <div> Arteries carry blood from heart to body. These face maximum pressure. Their function is to</div> <div> distribute blood to all the body tissues. Blood is pumped in the arteries by the heart with very</div> <div> high pressure that is why arteries are thick walled to withstand high pressure.</div> <div> Veins have to collect blood from the body and return it to the heart. Veins face less pressure,</div> <div> pressure almost negligible in major veins. Blood flow in major veins against gravitational</div> <div> pull and with low pressure so that veins have valves that prevent backflow of blood. In many</div> <div> parts of the body like arms and legs there are muscles that contract and relax to move the</div> <div> blood towards heart.</div> <div> Capillaries have to exchange materials with tissues; these originate from arteries and pass</div> <div> from tissues then joins to make veins. Capillaries have to carry out exchange of materials</div> <div> with the tissues that is why their walls are just one celled thick. Capillaries when enters</div> <div> tissues makes branches, where they branch groups of muscles are present which may open or</div> <div> close to increase or decrease the blood flow towards tissues.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 57</div> <div> Comparison of an artery and a vein</div> <div> Main arteries and veins in human arterial and venous systems</div> <div> head, shoulders, arms</div> <div> other body organs like kidneys, gonads, liver etc.</div> <div> Structure of human heart</div> <div> Heart in human beings is a muscular pump to push blood towards body and lungs. Heart in</div> <div> humans is of the size of a clenched fist. Heart consists of four chambers including 2 atria and</div> <div> 2 ventricles. Atria receive blood from body and lungs. Ventricles push blood from heart to</div> <div> body and lungs. These chambers (atria and ventricles) are connected to each other. At their</div> <div> junction valves are present, which are responsible to prevent backflow of blood.</div> <div> Left side of the heart, particularly ventricle is stronger because it has to push blood to the</div> <div> whole body in comparison to right side.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 58</div> <div> Structure of human heart</div> <div> Double pumping action of heart and role of valves</div> <div> Deoxygenated blood from body enters the heart through major veins (vena cava) to right</div> <div> atrium. When right atrium contract, blood enters the right ventricle. There is a valve called</div> <div> tricuspid valve that prevents backflow of blood. On the other side, oxygenated blood from</div> <div> lungs enters the left atrium and when left atrium contract it enters the left ventricle. At the</div> <div> junction of left atrium and ventricle another valve is present called bicuspid valve that</div> <div> prevents backflow of blood. Tricuspid and bicuspid valves are collectively called</div> <div> atrioventricular vales.</div> <div> In fact, both atria are filled at the same time and also contract at the same time to push blood</div> <div> in the ventricles. Both ventricles also contract at the same time to push blood toward body</div> <div> (left one) and lungs (right side). Right ventricle pushes blood in the pulmonary artery</div> <div> towards lungs. At this junction a valve is present called pulmonary valve that prevent</div> <div> backflow of blood from pulmonary arteries to right ventricle. Left ventricle pushes blood</div> <div> towards aorta, which is the main artery distributing blood the body. This junction is also</div> <div> guarded by a valve called aortic valve, which prevents backflow of heart from the aorta to</div> <div> left ventricle. Pulmonary and aortic valves are collectively called as semilunar valves.</div> <div> Self-excitatory system of the heart</div> <div> Heart has self-excitatory system. Heart has s group of muscles called sinoatrial node which</div> <div> produces impulse (electrical activity) that spread in the heart to contract its various chambers</div> <div> systematically. Impulse spread toward atria first and causes the atria to contract. Then it</div> <div> enters another node called atrioventricular node where its magnitude is increased and then</div> <div> it enters the ventricles and the ventricles contract. The self-excitatory group of muscles of the</div> <div> heart is called pace maker.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 59</div> <div> Cardiac Cycle</div> <div> Cardiac cycle is the time period from when the blood enters the heart to the time when blood</div> <div> is pushed by the heart. We can also say that it is the time period from artial and ventricular</div> <div> diastole to ventricular systole.</div> <div> Cardiac cycle consists of following steps:</div> <div> 1. Both atria and ventricles are relaxed. This is the time when both atria are filled with</div> <div> blood from body and lungs. All heart muscles are relaxed, which means that these are</div> <div> at diastole.</div> <div> 2. Then both atria contract and blood is pushed into ventricles. This is called atrial</div> <div> systole. At this time, both AV valves are open and both semilunar valves are closed.</div> <div> 3. Then the ventricles contract and push blood into aorta and pulmonary artery. This is</div> <div> called ventricular systole. With this, a cardiac cycle is complete.</div> <div> 4. Then again, both atria and ventricles are relaxed, i.e., come back to the initial state.</div> <div> Double Circulation</div> <div> Human circulatory system is called a double circulatory system because heart receives and</div> <div> sends blood from and to lungs (pulmonary circuit) and body (systemic circuit). Look at the</div> <div> diagram below for a detailed view.</div> <div> Systemic circulation</div> <div> ◦ From heart to body and vice versa</div> <div> ◦ Head, shoulders and arms</div> <div> ◦ Lower body organs</div> <div> Pulmonary circulation</div> <div> ◦ From heart to lungs and vice versa</div> <div> Double circulation in humans</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 60</div> <div> Exercise</div> <div> 1. Draw the structural diagram of human heart.</div> <div> 2. Differentiate between arteries and veins using diagrams.</div> <div> 3. Draw the structure of a capillary. Also describe the functions of capillaries.</div> <div> 4. Explain the significance of valves in preventing backflow of blood in heart.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 61</div> <div> Biology lecture # 9</div> <div> Respiratory System</div> <div> Lecture Outline</div> <div> Why respiration?</div> <div> Living organisms needs energy for their activities.</div> <div> Energy is extracted by complex metabolic processes from food or photosynthesis.</div> <div> Respiration is the process of exchange of gases to produce energy in biological form.</div> <div> What is respiration?</div> <div> Respiration consist of processes involves exchange of gases in living organisms or metabolic</div> <div> reaction to produce energy. Respiration is one of the most important metabolic activities. It is</div> <div> of two types:</div> <div> o Organismic respiration consists of breathing or ventilation, i.e., inhalation</div> <div> and exhalation movements and gas exchange.</div> <div> o Cellular respiration consist of metabolic reactions to produce energy by</div> <div> utilization of oxygen, production of carbon dioxide and extracting and</div> <div> conserving energy from food molecules in biological form, such as ATP.</div> <div> Cellular respiration</div> <div> Cellular respiration is of two types:</div> <div> o Aerobic, in which oxygen is utilized to produce energy.</div> <div> Example is electron transport chain in mitochondria.</div> <div> o Anaerobic, in which oxygen is not involved but energy is produced using</div> <div> other molecules.</div> <div> Example is fermentation in some bacteria.</div> <div> Organismic respiration</div> <div> Organismic respiration is the ventilation or breathing, i.e., the movements which causes</div> <div> inhalation and exhalation. Air contains gases and exchange of gases occurs in the specialized</div> <div> organs, for example, lungs in humans.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 62</div> <div> Difference between cellular and organismic respiration</div> <div> · Cellular respiration is a series of events of metabolic reactions for production of</div> <div> energy.</div> <div> · Organismic respiration is the process of coordinated movements of body that results</div> <div> in inhalation and exhalation of air. We also call it breathing or ventilation.</div> <div> Respiration in air and water</div> <div> Respiration in air is easier in comparison to water because air is lighter and water is denser.</div> <div> Also, air is much more saturated with oxygen than water. So that gas exchange in air is easier</div> <div> in the water than in water.</div> <div> Respiration in plants</div> <div> Gas exchange in plants occurs by stomata in mesophyll cells. Stomata are openings guarded</div> <div> by guard cells; these are used for transpiration in plants through water vapors. Roots of land</div> <div> plants get the oxygen required by the plants from air present in soil. Aquatic plants acquire</div> <div> their oxygen from oxygen dissolved in water.</div> <div> Respiration in animals</div> <div> In animals, respiration occurs by means of specialized organs, for example gills in fishes and</div> <div> lungs in terrestrial animals. The most important property of the respiratory organs is</div> <div> respiratory surfaces that support and facilitate the process of repiration.</div> <div> Properties of Respiratory surfaces</div> <div> Properties of Respiratory surfaces include a large and moist surface area, a thin epithelium,</div> <div> ventilation (air availability) and a capillary network.</div> <div> Respiration in some small animals</div> <div> In small animals, respiration occurs by means of general body surface or specialized systems.</div> <div> Hydra is an aquatic organism, which have a mouth and body cavity through which water</div> <div> moves in and out. Cells of the inner body wall exchange gases with that water. Cells of the</div> <div> epidermal layer exchange gases with the water.</div> <div> In some other organisms like earthworms which have a closed circulatory system the</div> <div> exchange of gases takes place by the capillaries, which are present in closed vicinity with the</div> <div> body wall.</div> <div> In the arthropods, especially insects like cockroach a very special system of gas exchange</div> <div> exist called the tracheal system. Tracheal system is a system of tubes which are extensions</div> <div> of the body wall and makes a network of tubes called tracheae, tracheoles and air sacs in</div> <div> the body. These have openings to the exterior called spiracles. Air enters in through spiracles</div> <div> and enters the trachea and tracheoles, which are present close to the tissues. Gas exchange is</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 63</div> <div> easier because in trachea only air is present, which is a very lighter medium. Tracheal system</div> <div> is a very efficient system of respiration.</div> <div> Respiration in fish, frog and birds</div> <div> Fishes</div> <div> Fishes are aquatic animals; these have respiratory organs called gills. Water enters through</div> <div> mouth into the gills where gas exchange occurs and then water move out from gills. Heart is</div> <div> fishes is called a single circuit heart, which pumps blood towards gills where gas exchange</div> <div> occurs and then blood moves towards body.</div> <div> Frogs</div> <div> Frogs are called a transition between aquatic and land animals. These live in water and land</div> <div> both. These have three different types of respiratory system at different stages of life. When a</div> <div> frog is hatched for an egg and becomes a larva, it lives in water and respires through gills.</div> <div> When it becomes an adult frog it respires by lungs and skin. Frog’s skin has a network of</div> <div> blood capillaries so that gas exchange may occur there.</div> <div> Birds</div> <div> Birds have a very efficient system of respiration. Birds respire through lungs. They also have</div> <div> air sacs in their in their body and bones, which also helps in capturing air and hence</div> <div> efficiency of gas exchange is improved.</div> <div> Respiratory organs</div> <div> Land animals have their respiratory organs named lungs. In aquatic animals, gills are the</div> <div> organs for gas exchange.</div> <div> Respiratory system in humans</div> <div> Respiration in human beings occurs by lungs and associated air passageways. Human</div> <div> respiratory system consists of:</div> <div> Air passageways in humans</div> <div> o Nostril and nasal cavity</div> <div> o Pharynx</div> <div> o Larynx</div> <div> o Trachea</div> <div> o Bronchi</div> <div> o Bronchioles</div> <div> Lungs in humans</div> <div> o Pleural cavity</div> <div> o Body of lungs</div> <div> o Alveoli – the smallest units</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 64</div> <div> Lungs inhuman beings</div> <div> Structure and functions of various parts of air passageways</div> <div> Nose and nasal cavity</div> <div> Nose is the part for inhalation. Nose and nasal cavity is lined with ciliated epithelium and its</div> <div> surface is covered with mucus. The ciliated and moist surface traps dirt and other particles.</div> <div> The air, which enters inside is filtered, moist and warm.</div> <div> Pharynx</div> <div> It is a small muscular passage, which is lined with mucous membrane. Air moves down to</div> <div> larynx through pharynx.</div> <div> Larynx: the voice box</div> <div> Larynx is a complex cartilaginous structure, through which air moves down to trachea. Its</div> <div> opening is ciliated and covered with mucous. Mucus membrane is stretched across into thin</div> <div> edged fibrous bands called vocal cords. Vocal cords help in voice production.</div> <div> Trachea (windpipe)</div> <div> Trachea is a long tube stretched from larynx to lungs. It has a tubular structures and it lies</div> <div> ventral to the esphagous. It has C-shaped cartilaginous rings which are supporting structure</div> <div> and prevent tracheal collapse. Trachea extends through the chest cavity or thorax. In thorax, it</div> <div> divides into 2 tubes called bronchi one entering each lung.</div> <div> Bronchi, bronchioles and alveoli</div> <div> Trachea divides to form bronchi in thorax region. Bronchi enter the lungs and divide further</div> <div> to make bronchioles (when they attain a diameter of 1mm or less). Bronchi have same</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 65</div> <div> cartilaginous rings but these become irregularly distributed plates when reaches at the end of</div> <div> bronchioles.</div> <div> Alveoli</div> <div> Brochioles keep dividing further and enter deep into the lungs to give rise to air sacs. Air sac</div> <div> is the functional unit of lungs. Air sacs consist of several microscopic structures called</div> <div> alveoli. Alveoli and air sacs are covered by a network of capillaries. This network is the site</div> <div> of gas exchange.</div> <div> Functional units of lungs</div> <div> Structure of lungs</div> <div> There is a pair of lungs, one is right and other is left. These are present in chest cavity. Lungs</div> <div> are protected by ribs and pleural cavity (double membrane fluid filled cavity). Lungs are</div> <div> spongy in structure because of the presence of millions of alveoli. Below lungs a muscular</div> <div> floor of the chest is present, which is called diaphragm.</div> <div> Breathing</div> <div> Breathing is the process of inhalation and exhalation. Lungs are spongy, cannot pull or push</div> <div> air themselves. Breathing movements occurs with the help of pressure and movements of</div> <div> diaphragm. Diaphragm is dome-like structure present as the floor of chest cavity. When it is</div> <div> contracted, it becomes less dome-like, which results in expansion of chest and inhalation of</div> <div> air. When it is relaxed then it becomes more dome-like and pressure in the chest is decreased,</div> <div> which results in exhalation of air. When muscles between the ribs contract, the rib cage is</div> <div> elevated; and when relax, ribs settle down. This movement also helps in the process of</div> <div> breathing.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 66</div> <div> Exchange of gases in alveoli</div> <div> Gases are exchanged against a pressure difference in the blood and lungs (alveoli). Blood</div> <div> capillaries are distributed around alveoli in very thin layers. Blood cells and alveolar air are</div> <div> very close for exchange of gases. Gases are exchanged at the alveoli.</div> <div> Hemoglobin (Hb) in blood cells help in exchange of oxygen against the concentration</div> <div> difference.</div> <div> Hb + O2 HbO2 (reversible if pressure of gases in air is changed)</div> <div> Transport of CO2</div> <div> Carbon dioxide is more soluble and dissolves in tissue fluids. From here it enters into blood</div> <div> capillaries. Carbon dioxide is transported in blood as:</div> <div> o 20 % as carboxyhemoglobin</div> <div> o 5% by few plasma proteins</div> <div> o About 70 % as bicarbonate ions combined with sodium.</div> <div> o CO2 + H2O –Carbonic anhydrase- H2CO3</div> <div> o H2CO3 H+ + HCO3-</div> <div> Figure showing association of the alveoli with blood capillaries in lungs.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 67</div> <div> Factors affecting gas exchange</div> <div> · Carbon dioxide</div> <div> o If CO2 increases then O2 tension decreases. The result is that capacity of</div> <div> hemoglobin for O2 is reduced.</div> <div> · Temperature</div> <div> o Rise in temperature decreases the oxygen carrying capacity of hemoglobin.</div> <div> · pH</div> <div> o If pH declines then oxygen carrying capacity declines.</div> <div> · H+ ions bind to hemoglobin to decrease oxygen carrying capacity.</div> <div> Lung capacity and effect of exercise on breathing rate</div> <div> In humans, fully inflated lungs have a capacity of 5 liters. Normally, at rest or sleep exchange</div> <div> is half a liter. During exercise, it may increase up to 3.5 liters. It means that there is a 1.5 L</div> <div> residual volume that cannot be expelled. Inhalation per minute is 15-20 times; during exercise</div> <div> it may be up to 30 times to fulfill the needs of exercising muscles.</div> <div> Changes in composition of breathed air</div> <div> Gas Inhaled air Exhaled air</div> <div> Oxygen 21 % 16%</div> <div> Carbon dioxide 0.04% 4%</div> <div> Nitrogen 79% 79%</div> <div> Water vapors Variable Saturated</div> <div> Exercise</div> <div> 1. Differentiate between cellular and organismic respiration.</div> <div> 2. Draw the structure of human lungs.</div> <div> 3. What are characteristics of a respiratory surface?</div> <div> 4. How exercise affects the breathing process?</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 68</div> <div> Biology lecture # 10</div> <div> Excretory System</div> <div> Introduction and need of excretion</div> <div> Living organisms have to metabolize which consist of anabolism and catabolism. Anabolism</div> <div> consists of all reactions for formation of compounds. Catabolism is break down of various</div> <div> compounds including glucose, proteins and lipids for the formation of energy.</div> <div> Catabolism of carbohydrates, proteins and lipids</div> <div> carbohydrates + oxygen CO2 + H2O + energy</div> <div> proteins + oxygen CO2 + H2O + NH3 + energy</div> <div> lipids + oxygen CO2 + H2O + energy</div> <div> Metabolic wastes</div> <div> We can see in the reactions above that metabolic waste products are carbon dioxide, water</div> <div> and ammonia. These are waste and surplus materials. These have to be removed. Ammonia is</div> <div> highly toxic for the tissues. Water and CO2 are dangerous for the body if these are present in</div> <div> excess. Rise in CO2 may result in decrease in pH in blood which is dangerous. Ammonia is</div> <div> highly toxic and has to be converted into less toxic form. But those forms also need to be</div> <div> removed. Changes in water concentration in tissue fluids also create problems. Higher</div> <div> concentration may cause dropsy, which is accumulation of water in tissues. Decrease in water</div> <div> concentration may lead to dehydration. For all of these reasons an excretory system is</div> <div> required.</div> <div> Excretion in Vertebrates</div> <div> Major waste products in vertebrates</div> <div> · Carbon dioxide</div> <div> · Mineral salts</div> <div> · Urea</div> <div> · Creatinine</div> <div> · Uric acid</div> <div> · Excess water</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 69</div> <div> Excretion in animals</div> <div> · Unicellular organisms</div> <div> · Small animals</div> <div> · Large animals</div> <div> · Adaptations to habitat</div> <div> o water - fresh and brackish e.g. marine</div> <div> o desert</div> <div> o terrestrial</div> <div> Excretory Organs</div> <div> · Skin acts as excretory structure</div> <div> · Salt glands are present in some marine or brackish water inhabiting organisms</div> <div> · Intestine sometimes act as excretory organ</div> <div> · Kidney</div> <div> o Major organ for excretion in vertebrates</div> <div> o Help also in osmoregulation</div> <div> · Structure of kidney is different in organisms living in fresh and marine waters.</div> <div> Kidneys in fresh water organisms is modified to produce dilute urine while kidneys of</div> <div> marine or brackish water inhabiting animals are designed to produce concentrated</div> <div> urine.</div> <div> Basic components of human excretory system: kidneys and accessory parts</div> <div> Various parts of human excretory system</div> <div> Kidney</div> <div> Adrenal gland</div> <div> Urinary bladder</div> <div> Urethra</div> <div> Ureter</div> <div> Renal artery</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 70</div> <div> External and internal structure of kidney</div> <div> Kidney is a bean shaped structure. A pair of kidneys is present in abdominal cavity attached</div> <div> to dorsal body wall. The concave part of kidney lies towards vertebral column. There is a</div> <div> depression present towards the vertebral column which is called hilus. The concave part</div> <div> provides space for entrance and exit of renal artery, vein and nerves. A thin tube ureter arises</div> <div> out of the concave part of kidney.</div> <div> Structure of a kidney</div> <div> Renal cortex and renal medulla</div> <div> If we look at a section of a kidney, then the outermost layer, reddish in color is called cortex.</div> <div> After cortex the second layer consists of structure like pyramids occur. This region is called</div> <div> medulla. A funnel shaped cavity is present towards inside that receives urine called renal</div> <div> pelvis.</div> <div> Nephron</div> <div> Nephron is the functional unit of kidney. Kidneys have many small structures present in</div> <div> cortex and medulla called nephrons. Function of the nephron is to produce urine. Nephron</div> <div> consists of following structures:</div> <div> ◦ Glomerulus, which is a capillary network.</div> <div> ◦ Bowman’s capsule (Glumerular capsule) is the capsule like structure in which</div> <div> the glumerulus is present.</div> <div> ◦ Convoluted tubule</div> <div> ◦ Loop of Henle</div> <div> ◦ Collecting duct</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 71</div> <div> Structure of a nephron</div> <div> Functioning of the kidney: Urine formation</div> <div> Function of the kidney is to produce urine. Kidney produces urine by following mechanism.</div> <div> Pressure Filtration</div> <div> Pressure filtration in the renal corpuscle occurs due to blood pressure in renal artery.</div> <div> Molecules other than RBCs and plasma are filtered, i.e., these enter into the renal</div> <div> capsule.</div> <div> It is called Bowman’s filtrate</div> <div> It consist of salts, glucose, urea and uric acid</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 72</div> <div> Filtration apparatus: Bowman’s capsule and glumerulus.</div> <div> Reabsorption</div> <div> The filtrate moves down the tubular system. Next step is called reabsorption. Reabsorption</div> <div> means that those compounds which are useful for the body return back to the blood and the</div> <div> remaining part of filtrate in the tubules makes urine consist of water and nitrogenous wastes.</div> <div> Reabsorption occurs through the network of capillaries surrounding the tubules. Reabsorption</div> <div> is selective process. Glucose, water and salts are reabsorbed.</div> <div> In the last step, only nitrogenous wastes remain inside the urine. This urine now goes down to</div> <div> pelvis and uretes. Through ureters it enters the urinary bladder for temporary storage. When</div> <div> bladder is full, there is a reflex for urination through urethra. Urination is not under conscious</div> <div> control in infants. In adults, however, this is under the conscious control through a sphincter</div> <div> present on the junction of urinary bladder and urethera.</div> <div> Osmoregulation</div> <div> Kidneys help in osmoregulation. This also helps in the maintenance of blood pressure. In case</div> <div> of increased blood pressure dilute urine is produced to temporarily reduce the quantity of</div> <div> water. In case of decreased blood pressure concentrated urine is produced and water is</div> <div> reabsorbed to compensate for fluid loss like in case of too much perspiration. Thirst is also a</div> <div> reflex in response to decreased quantity of water in blood.</div> <div> Exercise</div> <div> 1. Draw a labeled diagram of human kidney.</div> <div> 2. Describe the structure of human excretory system with the help of diagram.</div> <div> 3. Describe the process of urine formation.</div> <div> 4. Describe the role of kidneys in osmoregulation.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 73</div> <div> Biology lecture # 11</div> <div> Reproductive System</div> <div> Introduction of reproduction</div> <div> Reproduction is one of the basic characteristics of life. It is a biological process by which the</div> <div> organisms produce their young ones which are similar to their parents. This ability also</div> <div> allows organisms to adapt itself to the changing environment.</div> <div> Types of Reproduction</div> <div> There are two types of reproduction, asexual and sexual. In asexual reproduction, offspring</div> <div> are produced by simple cell division. No gametes are involved and offspring have same</div> <div> characteristics as their parents. In sexual reproduction, two organisms are involved in</div> <div> reproduction and offspring have characteristics which are combination of their parents and</div> <div> some new. Gametes are involved in this kind of reproduction. Sexual reproduction has</div> <div> advantage of increase in genetic variability. Gametes are formed by a process called meiosis</div> <div> in which alterations in genetic material takes place. As two organisms are involved, mixing of</div> <div> their characteristics takes place that increase more genetic variability. Genetic variability</div> <div> leads towards more adaptability to the environment.</div> <div> Types of asexual reproduction</div> <div> Asexual reproduction involves no gametes. There are many methods of asexual reproduction</div> <div> in organisms including:</div> <div> Binary fission</div> <div> Multiple fission</div> <div> Budding</div> <div> Regeneration</div> <div> Vegetative propagation in plants</div> <div> Binary fission</div> <div> This is a type of asexual reproduction in which one unicellular organism divides into two by</div> <div> simple division. In bacteria, for example, binary fission takes place:</div> <div> 1. Replication of single chromosome takes place.</div> <div> 2. Daughter chromosomes move towards opposite poles.</div> <div> 3. Cell membrane invaginates and meets in the center.</div> <div> 4. Cell wall follows the cell membrane and cell divides into two.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 74</div> <div> Binary fission also takes place in unicellular organisms like amoeba and paramecium. In</div> <div> these organisms:</div> <div> 1. nucleus elongates and divide into two</div> <div> 2. Cytoplasm also divides and cell divides into two</div> <div> Process of binary fission</div> <div> Multiple fission</div> <div> This is a process in which a single cell divides into many cells. For example amoeba makes a</div> <div> cyst in unfavorable conditions. Its nucleus divides into many nuclei and every part is</div> <div> surrounded by some cytoplasm. When favorable conditions come, the cyst split into many</div> <div> cells, each one a new amoeba.</div> <div> Multiple Fission results in production of many daughter cells.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 75</div> <div> Budding</div> <div> In this process an outgrowth (called bud) appears on the surface of an animal and may</div> <div> separate later on to develop into a new organism. Examples are yeast, hydra.</div> <div> Budding in yeast</div> <div> Regeneration</div> <div> Regeneration is the formation of lost part of the body. Examples are starfish and planaria. If</div> <div> their one body part is lost then they have ability to grow it again. In star fish an arm is lost</div> <div> then the arm grows again.</div> <div> Regeneration in planaira</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 76</div> <div> Vegetative propagation in plants</div> <div> It is a process that involves the vegetative propagation of some plant part such as stem or</div> <div> leaves. Examples are runners, suckers. Runners like grasses and strawberry and suckers like</div> <div> banana and mint.</div> <div> Adventitious roots are means of vegetative propagation.</div> <div> Sexual reproduction in Plants</div> <div> Flowering plants reproduce by sexual reproduction. Flowers have male and female parts</div> <div> called stamen and carpel. Fertilization occurs with the help of a process called pollination,</div> <div> i.e., transfer of pollen grains from anthers of stamen to carpel and then ovary. Pollination is of</div> <div> two types: self-pollination and cross pollination.</div> <div> Formation of seed and fruit</div> <div> Seed is formed from the zygote. It consists of embryo and its food.</div> <div> When the seed are formed then the wall of ovary becomes fleshy or scaly and</div> <div> forms fruit wall.</div> <div> The floral parts (sepals, petals etc.) fall off.</div> <div> The ripened ovary is called fruit.</div> <div> Sexual reproduction in Animals</div> <div> In animals, it occurs through fertilization of gametes (sperms and ova). Gametes are produced</div> <div> by meiosis which is the reduction division. These have half a number of chromosomes.</div> <div> Females and males are different in only one pair of chromosomes. Males have a chromosome</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 77</div> <div> different called a Y chromosome in one pair. So females have an XX pair while males have</div> <div> XY.</div> <div> Example of Frogs</div> <div> · Frogs carry out sexual reproduction.</div> <div> · Female frog lays a large amount of ova in water and male release sperms on these.</div> <div> · Sperms and ova fertilize to produce zygote.</div> <div> · Zygote the divide by mitosis to develop a larva which lives in water for a specific</div> <div> period of time and then by a process called morphogenesis develops into adult frog.</div> <div> Reproductive system in humans</div> <div> Humans reproduce sexually by fertilization of gametes called sperms and ova. Gametes are</div> <div> produced by specialized organs called testes and ovaries. Gametes have a haploid number of</div> <div> chromosomes, i.e., 23 chromosomes. 22 of these pairs are alike but 23rd pair is different in</div> <div> males and females. Females have X chromosomes in their gamete while males have an X or</div> <div> Y. Gender of the child is hence determined by the sperm, X or Y. Female always contribute</div> <div> an X in gamete. If male gamete has a Y then a male child will be produced. If sperm have an</div> <div> X then female child will be produced.</div> <div> Basic components of male reproductive system</div> <div> Human male reproductive system consists of a pair of gonads called testes, and a system of</div> <div> accessory tubes. (testis: sing.; testes: plural). Testes are paired which produces sperms. Testes</div> <div> lie outside the body in the sac called scrotum. From testes, sperms are transferred to main</div> <div> duct called vas deferns. Vas deferns makes a complex system of ducts called epididymis.</div> <div> From epididymis, sperms pass through the urinogenital tract and discharged.</div> <div> Function of testes</div> <div> Function of testes is to produce sperms and the male hormone testosterone. Testis consists of</div> <div> a system of tubules called seminiferous tubules.</div> <div> Process of Spermatogenesis</div> <div> 1. In the seminiferous tubules, germinal epithelium produces the cells called</div> <div> spermatogonia.</div> <div> 2. Spermatogonia divide into primary spermatocytes (2N).</div> <div> 3. Primary spermatocytes undergo meiosis to produce secondary spermatocytes (N).</div> <div> 4. Secondary spermatocytes divide further to make 4 haploid cells called spermatids.</div> <div> 5. Spermatids are converted to sperms by morphological changes.</div> <div> Testis also has some large cells in seminiferous tubules called sertoli cells. These cells</div> <div> provide support and nourishment to the developing sperms.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 78</div> <div> Mature sperm</div> <div> Basic components of female reproductive system</div> <div> Female reproductive system consists of a pair of ovaries and an associated system of tubes. A</div> <div> pair of ovaries lies inside the female body cavity which produces ova. Ovaries leads to the</div> <div> tubes called oviducts also called fallopian tubes. Oviduct opens into uterus. Ovum is</div> <div> fertilized in the oviducts then it passes to the uterus where it is implanted. A placenta is</div> <div> established between the uterine and fetal tissues for the exchange of materials. Uterus is</div> <div> connected to the vagina through cervix.</div> <div> Function of ovaries</div> <div> Function of ovaries is to produce ova and female hormones estrogen and progesterone. Germ</div> <div> cells in ovary produce many cells called oogonia.</div> <div> Process of Oogenesis</div> <div> 1. Oogonia produce primary oocyte (2N) by mitosis.</div> <div> 2. The primary oocyte divides by meiosis into secondary oocyte (N) and a polar body.</div> <div> 3. The secondary oocyte divides to form one ovum and a polar body.</div> <div> 4. The first polar body also divides to form 2 polar bodies.</div> <div> 5. Hence from secondary oocyte, one ovum and three polar bodies are produced.</div> <div> Usually ovary releases one ovum at a time, this is called ovulation. Sometimes it releases</div> <div> more which may result into fraternal (non-identical) twins.</div> <div> Exercise</div> <div> 1. Draw the process of spermatogenesis.</div> <div> 2. Draw the process of binary fission in bacteria.</div> <div> 3. Draw the process of multiple fission in amoeba.</div> <div> 4. Differentiate the process of meiosis in males and females.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 79</div> <div> Biology lecture # 12</div> <div> Ecology I</div> <div> Ecology is the study of interactions among organisms and their environment.</div> <div> Environment</div> <div> The physical surroundings of an organism including air, water, soil etc. Organisms have to</div> <div> interact with environment. Environment provides organisms everything required to live.</div> <div> Environment is always changing, may be supportive or hostile. Organisms living in an</div> <div> environment are “best fit” for that particular environment.</div> <div> Environment consist of biotic and abiotic factors</div> <div> · Biotic factors</div> <div> o Animals, plants, fungi, algae, bacteria</div> <div> · Abiotic factors</div> <div> o Air, water, soil</div> <div> What is Ecology?</div> <div> · The study of interactions between organisms with each other and their environment.</div> <div> · Biosphere and environment.</div> <div> o Surface of Earth’s crust</div> <div> o Water bodies on Earth’s surface</div> <div> · Atmosphere that surrounds Earth</div> <div> Soil support life Rain helps in water availability</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 80</div> <div> Levels of Organization in an Ecosystem</div> <div> · Species</div> <div> · Population</div> <div> · Community</div> <div> · Ecosystem</div> <div> Then comes:</div> <div> · Biome</div> <div> · Biosphere</div> <div> Species: male and female Golden Pheasants</div> <div> Atmosphere • Air</div> <div> Hydrosphere • Waters</div> <div> Ecosphere • Ecosystems</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 81</div> <div> .</div> <div> Population is the group of organisms of same species living in an area.</div> <div> Ecosystem</div> <div> Ecosystem is the area where organisms live in interaction with non-living factors.</div> <div> Organisms and their environment</div> <div> Organisms live in specific locations or areas suitable for them. Habitat is the term used for</div> <div> physical location of organism. Another term is niche. Niche is defined as ecological role of</div> <div> organisms. Organisms interact with their surroundings; their interaction is termed as niche.</div> <div> Organisms and their environment</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 82</div> <div> Biotic and Abiotic Components</div> <div> · Living / Biotic Components of an Environment</div> <div> o Animals, plants; Interactions between organisms.</div> <div> · Non-living / Abiotic Components of an Environment:</div> <div> o Air, water; Interactions between organisms and their environment.</div> <div> Energy Flow in Ecology</div> <div> Main source of energy in an ecosystem is “Sunlight”. Autotrophs (producers) are the</div> <div> organisms which utilize the energy stored in inorganic compounds and use sunlight to make</div> <div> their food. These organisms carry out “photosynthesis” and use this energy to convert</div> <div> “carbon dioxide and water into oxygen and glucose”. The other type of autotrophs makes</div> <div> carbohydrates using chemical energy e.g., many bacteria. These are called chemoautotroph.</div> <div> Heterotrophs (consumers) are the organisms that cannot make their own food and depends</div> <div> upon organic source.</div> <div> o Herbivores (the organisms that eat plants, i.e., producers; also called primary</div> <div> consumers)</div> <div> o Carnivores (the organisms that eat herbivores or other carnivore animals)</div> <div> o Omnivores (the organisms that eat upon plants and animals both)</div> <div> Pyramids in Ecology</div> <div> · Decomposers (these are the organisms which break down the dead organic matter)</div> <div> · Consumers (the organisms which feed upon producers or other consumers)</div> <div> · Producers (the organisms which makes their own food by either using sunlight or</div> <div> inorganic chemicasl)</div> <div> Decomposers</div> <div> (e.g.,</div> <div> bacteria)</div> <div> Consumers (e.g.,</div> <div> animals)</div> <div> Producers (e.g., plants)</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 83</div> <div> An example of ecological Pyramid</div> <div> Food Chains are straight energy flow relationships in an ecosystem.</div> <div> Food Webs</div> <div> Food webs are complex energy flow pathways and relationships in an ecysystem.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 84</div> <div> An example of a terrestrial food web</div> <div> Introduction of the factors that affect the quality of environment</div> <div> Factors that Affect Environment</div> <div> · Air currents</div> <div> · Temperature</div> <div> · Soil</div> <div> · Water</div> <div> · Light</div> <div> Human interference</div> <div> Industrial effluents</div> <div> Industrial growth results in the production of more and more effluents. Industries produce</div> <div> effluents which may be solid or liquid. These may contain heavy metals, toxic chemicals.</div> <div> These are disastrous for the biodiversity. These should be treated well. The solution is</div> <div> treatment plants for removal of dangerous materials.</div> <div> Deforestation</div> <div> Forests are cut down for wood; wood may be used in buildings, furniture etc. Forests are also</div> <div> cut for making towns. This result in destruction of habitats of organisms which may leads to</div> <div> extinction of many organisms. As organisms are related, results may be increase or decrease</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 85</div> <div> of number of other organisms, e.g., if sparrows are decreased then insect pests may increase</div> <div> and destroy crops in that area.</div> <div> Human interference: littering by the tourists.</div> <div> Urban spread</div> <div> As populations are increasing there is an increasing need of towns and cities. Urban spread</div> <div> requires the cutting of forests or other type of habitat destruction.</div> <div> Construction of dams, waterways</div> <div> Dams and water ways etc are constructed on water bodies. These may result in habitat</div> <div> destruction of fish and other aquatic animals. Loss of biodiversity results in instability of</div> <div> ecosystem.</div> <div> Agriculture</div> <div> Agriculture also affect environment. In grasslands keeping too many animals may result into</div> <div> loss of grass and destruction of ecosystem. In crop growing fields fertilizer use and growing</div> <div> exhaustive crops (the crops that uses much of soil’s resources) may result in damage to the</div> <div> ecosystem.</div> <div> Natural factors</div> <div> Natural disasters like floods, earthquakes etc. may lead towards total or partial habitat</div> <div> destruction. Both biotic and abiotic factors are affected. The whole structure of ecosystem</div> <div> may change.</div> <div> Importance of environment for the healthy living of organisms</div> <div> Organisms have to live in environment</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 86</div> <div> Organisms need food, shelter and other resources. If the balance of environment is changed</div> <div> by extinction of an organism or some other factor then many organism in the food chain or</div> <div> web are disturbed. A balanced ecosystem is required for healthy living of organisms.</div> <div> Exercise</div> <div> 1. Differentiate between niche and habitat.</div> <div> 2. Describe the effects of human interference on ecosystems.</div> <div> 3. Define the following:</div> <div> a. Population</div> <div> b. Community</div> <div> c. Ecosystem</div> <div> d. Biosphere</div> <div> 4. Describe some abiotic and biotic factors of an ecosystem.</div> <div> 5. Draw a typical water ecosystem.</div> <div> 6. Draw a typical example of terrestrial ecosystem.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 87</div> <div> Biology lecture # 13</div> <div> Ecology II - Ecosystems</div> <div> Ecosystems - An Introduction</div> <div> Ecosystem is an area where the organisms are living in an area in interactions with each other</div> <div> and their physical surroundings. There are many types of ecosystems, mainly divided into</div> <div> two categories:</div> <div> o Aquatic ecosystems (ecosystem in water)</div> <div> o Terrestrial ecosystems (ecosystem on land)</div> <div> An aquatic ecosystem</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 88</div> <div> Basic components of an ecosystem; and their roles / significance</div> <div> Ecosystem consists of:</div> <div> · Abiotic factors</div> <div> o Air, water, soil</div> <div> o Temperature, pH, humidity</div> <div> · Biotic factors</div> <div> o Animals, plants, protists, bacteria</div> <div> Biotic components</div> <div> · Producers</div> <div> o Plants, algae</div> <div> · Consumers</div> <div> o Animals</div> <div> · Decomposers</div> <div> o Fungi, bacteria</div> <div> Pyramids in Ecosystems</div> <div> Ecological relationships are also shown in the form of pyramids in ecology. These are called</div> <div> ecological pyramids or trophic levels. On the base come producers, then consumers and then</div> <div> decomposers.</div> <div> A pyramid</div> <div> Decomposers</div> <div> (e.g.,</div> <div> bacteria)</div> <div> Consumers (e.g.,</div> <div> animals)</div> <div> Producers (e.g., plants)</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 89</div> <div> Producers</div> <div> The living organisms which make their own food are called producers. Examples include</div> <div> plants, bacteria and algae. They carry out photosynthesis, carbon dioxide and sunlight to</div> <div> water and oxygen. They synthesize carbohydrate by a process called Calvin’s cycle. Entry</div> <div> point of energy in the ecosystem is producers.</div> <div> Consumers</div> <div> These are the organisms that uses organic carbon source. These use carbohydrates produced</div> <div> by plants. Types include primary, secondary and tertiary consumers. Consumers include</div> <div> herbivores, carnivores and omnivores.</div> <div> Consumers</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 90</div> <div> Decomposers</div> <div> These organisms feed upon dead organic matter. These include fungi and bacteria.</div> <div> Abiotic components of Ecosystem</div> <div> Water, Light, Air and Soil</div> <div> · Water is a limiting factor in an ecosystem. It is required by living organisms.</div> <div> Organisms have to adapt according to the availability of water.</div> <div> · Sun light is the primary source of energy, e.g. zones of a lake.</div> <div> · Air manages temperature and other things.</div> <div> · Soil supports life.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 91</div> <div> ECOSYSTEMS – EXAMPLES</div> <div> Climate and weather affect the ecosystem. There are various ecosystems in the world and in</div> <div> Pakistan according to the climate of the area.</div> <div> Aquatic Ecosystems</div> <div> Water is a liquid medium to support life. Aquatic ecosystems may be of fresh water or</div> <div> marine; a lake or a sea.</div> <div> Water has some properties</div> <div> · It changes its temperature slowly; more appropriate for life.</div> <div> · It absorb considerable amount of energy (sunlight) but at depths its level decreases for</div> <div> photosynthesis.</div> <div> · Nutrients are concentrated at bottom.</div> <div> · Water is abundantly available in this ecosystem.</div> <div> Fresh water lakes</div> <div> · Lakes vary in nutrient, physical conditions and depths.</div> <div> · Life also varies according to the conditions.</div> <div> · Lakes have three zones:</div> <div> o Littoral – shallow water, photosynthesis occur, most diverse, anchored plants,</div> <div> submerged plants, phyto and zooplankton and fishes.</div> <div> o Limnetic – upper layer of deep water, have good light penetration, photosynthesis</div> <div> occur, cynobacteria – protozoans – crustaceans and fishes.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 92</div> <div> o Profundal – bottom layer of deep part, almost no light for photosynthesis, high</div> <div> nutrients on bottom, bacteria – decomposers.</div> <div> Human interference</div> <div> Wastes comes from different areas and results in eutrophication. Excessive growth of</div> <div> cyanobacteria creates a scum on the surface; result is that plants and animals die.</div> <div> Decomposer bacteria further decompose result in more organic matter. Ultimately habitat</div> <div> destruction is the result.</div> <div> Terrestrial Ecosystems</div> <div> Plants and animals adapts to the changes from water to land habitat. Supporting tissue</div> <div> developed for the purpose; animals have skeleton and plants have vascular bundles to support</div> <div> these organisms on land. Water conservation is another adaptation to conserve water.</div> <div> Types of Terrestrial Ecosystems</div> <div> Divided into four main types:</div> <div> o Forest ecosystems</div> <div> Tropical rain forests</div> <div> Temperate deciduous forests</div> <div> Coniferous alpine and boreal forests</div> <div> o Grassland ecosystems</div> <div> o Desert ecosystems</div> <div> · Tundra ecosystems</div> <div> Major ecosystems in Pakistan</div> <div> · Pakistan has a variety of climate and seasons.</div> <div> · Have these main ecosystems:</div> <div> o Temperate deciduous forests – Shogran and Neelum valley</div> <div> o Coniferous alpine and boreal forests – Kaghan, Malam Jabba, Dir and Chillas</div> <div> o Grassland ecosystems – Gilgit, Kashmir, Waziristan, Chitral and Kallat</div> <div> o Desert ecosystem – Mianwali, Bahawal Nagaar, Bahawalpur and more, Thal,</div> <div> Thar and Cholistan</div> <div> o Tundra ecosystem – mountains of Karakoram and Hindukash</div> <div> Temperate deciduous forest</div> <div> · Present in Southeast Asia, India, North America, China, Japan etc.</div> <div> · Have moderate temperature – 4 – 30 C</div> <div> · Rain fall 750 to 1500 mm</div> <div> · Plants – Taxus, Pinus, Berberis, ferns, grasses, herbacious; shed their leaves in dry</div> <div> season</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 93</div> <div> · Animals – Rehesus monkeys, leopard, black bears</div> <div> · Soil - very fertile and rich in nutrients</div> <div> · Humans hunt animals and cut wood</div> <div> Coniferous alpine and boreal forest</div> <div> • Eurasia, North America, Canada</div> <div> • Low temperature – freezing to 10C</div> <div> • Snow cover is present</div> <div> • Harsh climate – less suitable for life</div> <div> • Highly adapted species lives here, Marco polo sheep, bisons, wolf, black bear</div> <div> • Plants – Pinus species grow; have long waxy needle like leaves to survive cold</div> <div> • Human disturbs less because less accessible</div> <div> Grassland ecosystem</div> <div> · Pakistan, Eurasian countries, North America</div> <div> · Two types – Prairies, Savana</div> <div> · Rain fall 250-750 mm, water is a crucial factor</div> <div> · Plants are grasses – tall and short, legumes, herbs, mosses, lichens</div> <div> · Animals are reptiles, amphibians, mammals</div> <div> · Decomposers are fungi, bacteria</div> <div> · Human impact – agriculture and live stock</div> <div> Desert ecosystem</div> <div> · Rain fall – 25-50 mm</div> <div> · Perennial plants, cacti, succulent leaves and stems</div> <div> · Animals adapt to little water, kangroo rats, reptiles, birds</div> <div> · Human impact – desertification</div> <div> Tundra ecosystem</div> <div> · Very cold, snowy</div> <div> · Small perennial flowers</div> <div> · Mosquitoes grow well, birds feed upon these (geese, ducks)</div> <div> · White bears, foxes, snow owls are present</div> <div> · Human interference can produce long lasting effects because plants grow slowly but</div> <div> this interference is low due to harsh weather</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 94</div> <div> A monkey in Ayubia National Park</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 95</div> <div> Monkeys in Ayubia National park, you can see the solid wastes behind these.</div> <div> Black bear which was once found in the Ayubia National Park</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 96</div> <div> A beautiful ecosystem.</div> <div> Exercise</div> <div> 1. What is an ecosystem? Name some areas of Pakistan that have desert ecosystems.</div> <div> 2. With the help of a drawing show the grassland ecosystem.</div> <div> 3. Describe various components of an aquatic ecosystem with the help of a diagram.</div> <div> 4. List some effects of human interference on ecosystems.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 97</div> <div> Biology lecture # 14</div> <div> Food Chains and Food Webs</div> <div> Ecosystem</div> <div> An area where the organisms are living in interactions with each other and their physical</div> <div> surroundings is called an ecosystem. There are many types of ecosystems, mainly divided</div> <div> into two categories:</div> <div> o Aquatic ecosystems (water ecosystems)</div> <div> o Terrestrial ecosystems (land ecosystems)</div> <div> Ecosystem</div> <div> Ecosystem consist of biotic (living) and abiotic (non living) components.</div> <div> · Biotic factors:</div> <div> o Producers, Consumers, decomposers</div> <div> o Plants, animals, fungi / bacteria</div> <div> Biotic factors are in relationship with each other in an ecosystem. These also interact with</div> <div> abiotic factors present in their surroundings like air, water, sunlight.</div> <div> Trophic levels</div> <div> Trophic levels or feeding levels in an ecosystem define roles of the groups of organisms.</div> <div> · Producers</div> <div> o Plants, algae</div> <div> o Consumers</div> <div> o Animals</div> <div> o Decomposers</div> <div> · Decomposers</div> <div> o Fungi, bacteria</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 98</div> <div> Pyramids in Ecosystems</div> <div> Autotrophs – Producers</div> <div> These are the organisms that make their own food using sunlight as an energy source. These</div> <div> convert carbon dioxide and water into carbohydrates. Producers are the only source for all</div> <div> organic food in the planet Earth; this is the entry point of energy. These provide food to all</div> <div> other life forms. Examples include plants, algae.</div> <div> Chemotrophs</div> <div> These are the organisms, which uses inorganic chemicals as energy source and makes</div> <div> carbohydrates. These lives in deep oceans, where there is no light source. Examples are some</div> <div> bacteria and deep sea worms.</div> <div> Heterotrophs – Consumers</div> <div> Organisms that do not make their own food and get food from other organisms are called</div> <div> consumers. They get energy by eating either plants or other animals. Their source of food</div> <div> hence is organic compounds produced by producers. Examples are small and large animals.</div> <div> Decomposers</div> <div> (e.g.,</div> <div> bacteria)</div> <div> Consumers (e.g.,</div> <div> animals)</div> <div> Producers (e.g., plants)</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 99</div> <div> Types of Consumers</div> <div> Consumers are divided into three classes:</div> <div> [[</div> <div> ◦ Primary consumers – herbivores (plant eaters)</div> <div> e.g., goats, cows</div> <div> ◦ Secondary consumers – primary carnivores (meat eaters that eat herbivores)</div> <div> e.g., frogs, snakes</div> <div> ◦ Tertiary consumers – secondary carnivores (meat eaters that eat other meat</div> <div> eaters)</div> <div> e.g., eagle, hawk</div> <div> Goat – herbivore Squirrel - herbivore</div> <div> Cat - carnivore</div> <div> Decomposers</div> <div> These are the organisms that eat dead organic matter. These feed upon animals and plants –</div> <div> their fallen parts or dead organisms. These recycle food in the ecosystem, convert non</div> <div> available organic matter into available matter for producers.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 100</div> <div> Food chains</div> <div> What is a food chain?</div> <div> Food chain is a one-way flow of energy in an ecosystem.</div> <div> Producers to consumers to decomposers</div> <div> In an ecosystem different food chains exist. This is a relationship of eating and being eaten.</div> <div> Example of a food chain from land (grassland) ecosystem</div> <div> Grassland ecosystem has following characteristics:</div> <div> o Rain fall 250-750 mm, water is a crucial factor</div> <div> o Plants are grasses – tall and short, legumes, herbs, mosses, lichens</div> <div> o Animals are reptiles, amphibians, mammals</div> <div> o Decomposers are fungi, bacteria</div> <div> Sunlight Grass Primary consumer (Rat/Mole)</div> <div> Tertiary Consumer (Hawk) Secondary Consumer (snake)</div> <div> A grassland ecosystem food chain</div> <div> Example of a food chain from aquatic ecosystem</div> <div> · Aquatic ecosystem is marked by:</div> <div> o Water, which is a liquid medium to support life.</div> <div> o May be fresh water or marine; a lake or a sea.</div> <div> · Light, temperature penetration is important for biodiversity.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 101</div> <div> A Simple Food Chain in a Lake</div> <div> Arctic ecosystem</div> <div> Food web</div> <div> What is a food web?</div> <div> · A network of eating and being eaten.</div> <div> · Feeding relationships between organisms are not as simple as food chains.</div> <div> · There is a diversity of organisms and one organism may be eaten by more than one</div> <div> other organisms.</div> <div> · Example is grass is eaten by cows, buffaloes</div> <div> Example of a food web from land (grassland) ecosystem</div> <div> · Grassland ecosystem have small plants, reptiles, amphibians and mammals.</div> <div> · Grass is eaten by most of the herbivores.</div> <div> · Herbivores are eaten by more than one carnivores.</div> <div> A food web of Grassland Ecosystem</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 102</div> <div> Example of a food web from aquatic ecosystem</div> <div> Aquatic ecosystem has phytoplanktons, zooplanktons, plants, animals and decomposers.</div> <div> Food webs may be simple or complex starting from producers.</div> <div> A food web in an aquatic ecosystem</div> <div> Desert Ecosystem</div> <div> · Dry and hot environment.</div> <div> · Few specific plants.</div> <div> · Well adapted animals.</div> <div> A desert food web</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 103</div> <div> Forest Ecosystem</div> <div> · Dense vegetation, animal diversity is high</div> <div> · Simple to complex food webs</div> <div> Exercise</div> <div> 1. Draw a food chain in a grassland ecosystem.</div> <div> 2. Draw a food chain in an aquatic ecosystem.</div> <div> 3. Draw a food web in a forest ecosystem.</div> <div> 4. Draw a food web in a lake ecosystem.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 104</div> <div> Biology lecture # 15</div> <div> Algae and Fungi</div> <div> Algae are:</div> <div> The organisms range in size from microscopic unicellular to large sea weeds, demonstrate</div> <div> following characteristics:</div> <div> Major producers of oxygen</div> <div> Provide food for animals in various food chains</div> <div> Source of chemicals with pharmaceutical value</div> <div> Utilize carbon dioxide to reduce the greenhouse effect</div> <div> Source of valuable materials including biofuels, food and agar (part of media for</div> <div> microbial growth)</div> <div> Thrived for 1.5 billion years, are an integral part of the global ecosystem</div> <div> Distinguishing characteristics of algae, with examples</div> <div> Photosynthetic, autotrophic</div> <div> Eukaryotic, have cell wall consist of cellulose</div> <div> Classified by their:</div> <div> energy storage products</div> <div> cell walls</div> <div> colour (due to types and abundance of pigments their plastids)</div> <div> cellular organization</div> <div> Reproduce both asexually and sexually</div> <div> Asexually by mitosis</div> <div> Sexually when there is environmental stress</div> <div> Plus and minus gametes fuse to form zygospore which give rise to new</div> <div> organism e.g. chlamydomonas</div> <div> Some reproduce by conjugation like spyrogyra</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 105</div> <div> Volvox is algae consist of rounded colonies</div> <div> Types of Algae based upon the pigments</div> <div> Green algae (chlorophyll, soluble in organic solvents only, such as alcohol), 7000</div> <div> species</div> <div> Red algae (have “phycobilins” water soluble pigment) 4000 species, cosmeics, gelatin</div> <div> etc</div> <div> Brown algae 1500 species, weeds</div> <div> Golden brown algae (formation of petroleum products)</div> <div> Carotenoids are also algal pigments soluble in organic solvents</div> <div> Euglenoids, both plant and animal like characteristics</div> <div> Algae could be distinguished by cellular organization:</div> <div> Unicellular algae: species occur as single, unattached cells that may or may not be</div> <div> motile. For example, Chlamydomonas, Euglena.</div> <div> Filamentous algal species occur as chains of cells attached end to end. These</div> <div> filaments may be few to many cells long and may be unbranched or branched in</div> <div> various patterns. For example, Spirogyra.</div> <div> Colonial algae occur as groups of cells attached to each other in a nonfilamentous</div> <div> manner. For example, a colony may include several cells adhering to each other as a</div> <div> sphere, flat sheet, or other three-dimensional shape. For example, Volvox.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 106</div> <div> Spirogyra</div> <div> Distribution and Significance of algae</div> <div> Algae are widely distributed in various areas of the world in small to large water bodies.</div> <div> These are present in small ponds to huge oceans. Green algae are found almost everywhere.</div> <div> Red algae and brown algae are mostly marine organisms. Euglenoids are fresh water</div> <div> inhabitants. When algae grow a lot covering large area of water it is called algal blooms.</div> <div> Important producers of the planet Earth</div> <div> Algae are producers in many food chains particularly in aquatic ecosystems. These convert</div> <div> sunlight into energy and carbon dioxide into carbohydrates. These help in reducing the</div> <div> Greenhouse effect by absorbing carbon dioxide.</div> <div> Algae as human diet alternatives</div> <div> Agar is used in the place of gelatin to make gels in many foods. Weeds are part of the salads</div> <div> and other materials for making various kinds of salads and desserts. Some are used in making</div> <div> ice creams.</div> <div> Production of Agar</div> <div> These are also used in production of Agar which is material extracted from sea weeds and</div> <div> help in solidifying bacterial growth media.</div> <div> Agar is very important in scientific research</div> <div> Used to culture microorganisms on solid surface</div> <div> A plentiful and cheap source for growing microorganisms</div> <div> Used in almost all microbiology research laboratories, for example in clinical</div> <div> laboratory</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 107</div> <div> Agar medium to test bacterial growth and effect of an antibiotic on it</div> <div> Algal Biofuels</div> <div> Algae can produce huge biomass. This biomass could be used to convert into fuels like</div> <div> ethanol. Algae are potential source of biofuels.</div> <div> The Fungi</div> <div> Fungi are the heterotrophs and major decomposers which feed upon decaying organic matter.</div> <div> These range in size from microscopic to large ones. These include heterotrophs, symbionts</div> <div> and parasites.</div> <div> Mushroom</div> <div> Distinguishing characteristics of fungi, with examples</div> <div> Unicellular to multicellular</div> <div> Eukaryotic</div> <div> Body is made of long filaments of hyphae (singular: hypha) which form a mycelium</div> <div> (collection of hyphae)</div> <div> Have a cell wall, made up of chitin</div> <div> Reproduce both asexually and sexually</div> <div> Spores</div> <div> Mating of hyphae</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 108</div> <div> Some important groups of Fungi</div> <div> Phylum Zygomycota = the Bread Molds</div> <div> e.g. Rhizopus – black bread mold</div> <div> Phylum Ascomycota = the Sac Fungi</div> <div> e.g. Yeast</div> <div> Phylum Basidiomycota = the Club Fungi</div> <div> e.g. Mushrooms, puffballs, bracket fungi, rusts, smuts</div> <div> Phylum Deuteromycota = the Fungi Imperfecti</div> <div> e.g. Penicillium</div> <div> Life cycle of fungi</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 109</div> <div> Hyphae and mycelium; Spores on the top (fruiting bodies)</div> <div> Mating in fungi</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 110</div> <div> Habitats and Significance of fungi</div> <div> Fungi grow in almost every habitat imaginable, as long as there is some type of organic</div> <div> matter present and the environment is not too extreme. It is a diverse group; number of</div> <div> described species is somewhere between 69,000 to 100,000 (estimated 1.5 million species</div> <div> total). It is present in soil, water, or on foods. These may also live on animal or plant bodies.</div> <div> Mycorrhizae are the fungi associated with the roots of vascular plants. Lichens are the</div> <div> association between fungi and algae.</div> <div> Lichens</div> <div> Lichens consist of association between algae and fungi. It is a symbiotic association. These</div> <div> are usually the first inhabitants of a new ecosystem.</div> <div> Fungi are important reducers / decomposers</div> <div> Feed on dead organic matter</div> <div> Convert it to less toxic form</div> <div> Convert into useable form for plant’s use</div> <div> Food source and food spoilage</div> <div> Many fungi are source of food and many other spoils foods.</div> <div> Mushrooms</div> <div> Various types</div> <div> Poisonous to edible</div> <div> Used as food, protein source</div> <div> Some fungi cause spoilage of foods</div> <div> Bread molds</div> <div> Sources of medicines</div> <div> Some fungi are sources for medicines.</div> <div> Truffles</div> <div> Used in medicines</div> <div> Gorw inside soil</div> <div> Penicillium</div> <div> Source of penicillin</div> <div> Other drugs</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 111</div> <div> Pathogenic fungi causing diseases in plants and humans</div> <div> Many fungi are pathogenic and cause infections in animals, plants and human beings. These</div> <div> may cause skin infections, eye infections and others. Parasites can harm human beings and</div> <div> plant infections can damage crops.</div> <div> Yeast</div> <div> Yeast is a very important organism for biotechnology and food industry. It is used to make</div> <div> various biotechnological products. It is eukaryotic and better in making proteins in</div> <div> comparison to prokaryotes. It is also used in wastewater treatments because it absorbs heavy</div> <div> metals and converts other contaminants into less toxic form.</div> <div> Structure of yeast while budding</div> <div> Exercise</div> <div> 1. What are important characteristics of algae?</div> <div> 2. What are important uses of fungi?</div> <div> 3. What are lichens and their significance for ecosystems?</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 112</div> <div> Biology lecture # 16</div> <div> Animals and Their Importance</div> <div> Distinguishing Characteristics of Animals, with examples</div> <div> Consist of eukaryotic cells</div> <div> Multicellular organisms, from simplest sponges to complex animals like mammals</div> <div> Highly adapted to their environments</div> <div> Widely distributed, present in all types of aquatic to terrestrial ecosystems even in air,</div> <div> e.g., the birds</div> <div> Important parts of food chains as consumers of different levels</div> <div> Heterotrophic, rely on organic carbon sources</div> <div> Independently living or parasitic</div> <div> Reproduce asexually or sexually</div> <div> Very important for human beings and the ecosystems</div> <div> Diversity of animals</div> <div> These are widely distributed and are present in almost all habitats. There are two major</div> <div> groups including invertebrates and vertebrates. Animals are wild if these are living in natural</div> <div> habitat or these are termed as domestic if these are kept for some benefit or as pets. Animals</div> <div> are kept in captivity or controlled habitats if there is a need in zoological gardens and safari</div> <div> parks.</div> <div> Phyla of Invertebrates with examples</div> <div> Porifera</div> <div> These are simple animals with one opening as mouth and a body cavity. These are aquatic organisms.</div> <div> e.g. Sponges</div> <div> Two layered, no specific organ, porous body</div> <div> Highly specialized cells</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 113</div> <div> Leucosolenia</div> <div> Coelenterates</div> <div> The animals with 3 body layers. These have stinging cells which have a poison to paralyze or kill the</div> <div> prey.</div> <div> e.g. Jelly fishes which are marine</div> <div> Have simple organs</div> <div> Have stings, mouths, tentacles</div> <div> Aurelia – a jelly fish.</div> <div> The worms</div> <div> These are of different kinds including round worms, flat worms and earth worms.</div> <div> Regeneration: These have ability to regenerate their lost part.</div> <div> Parasites, decomposers</div> <div> Grow very long</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 114</div> <div> Earthworm and flat worm</div> <div> Arthropods, widely distributed</div> <div> These are one of the most diverse groups of animals. These organisms have an exoskeleton.</div> <div> Four major groups</div> <div> Arachnids (spiders)</div> <div> Crustaceans</div> <div> Insects</div> <div> Millipede, centipede</div> <div> Have sense organs, are segmented, have exoskeleton</div> <div> House fly Butterfly</div> <div> Molluska</div> <div> These organisms are specific to have shells around their soft bodies.</div> <div> Soft bodies, hard shells</div> <div> Aquatic mostly</div> <div> Snails, lobsters</div> <div> Some of these make pearls</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 115</div> <div> Sepia</div> <div> Echinoderms</div> <div> These are the animals with spiny skins hence called echinoderms (echino-spiny).</div> <div> Exclusively marine</div> <div> Have a water vascular system for the movement</div> <div> Examples are star fish, sea cucumber, brittle star</div> <div> Brittle star</div> <div> Importance of Invertebrates</div> <div> Invertebrates are very important part of lot of food chains hence important for stability of</div> <div> ecosystems</div> <div> For human use:</div> <div> Sponges are used widely in sound proofing, washing</div> <div> Worms are important parasites of domestic animals and human beings</div> <div> Insects are pests of many crops, many useful insects like honey bee, lac insect</div> <div> Lobsters makes pearls, cultured for pearls</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 116</div> <div> These are components of Food Webs</div> <div> Component of aquatic food webs</div> <div> Components of terrestrial food webs</div> <div> Maintain ecosystem stability, if one becomes extinct then the whole food chain or</div> <div> web may become disturbed.</div> <div> Role in Soil Fertility</div> <div> Some invertebrates are decomposers, e.g., Earthworm</div> <div> They feed upon dead organic matter and increase soil fertility</div> <div> When animals die their bodies become part of soil and decomposed to add nutrients to</div> <div> soil</div> <div> Parasitic Invertebrates</div> <div> These could harm the humans and also harm our domestic animals and crops. There are many</div> <div> treatments available for these.</div> <div> Ticks, mites, lice are ectoparasites</div> <div> Worms are endoparasites</div> <div> Leeches are ectoparasits</div> <div> Major Classes of Vertebrates and their Importance</div> <div> Vertebrates are the organisms with a vertebral column precisely with 3 main characteristics at any</div> <div> stage of their life including notochord, nerve cord and pharayngeal slits.</div> <div> Vertebrates are divided into:</div> <div> Fishes</div> <div> Amphibians</div> <div> Reptiles</div> <div> Birds</div> <div> Mammals</div> <div> Fishes</div> <div> Aquatic animals, occupies fresh water and marine habitats, widely distributed, bony or</div> <div> cartilaginous</div> <div> Have gills for gas exchange, 5 chambered single circuit heart</div> <div> Have streamlined and slimy body, ectotherms</div> <div> Have fins (appendages) and tail</div> <div> Cultured in ponds and caught from natural habitats, are important food source of proteins</div> <div> Cultured for ornamental purposes</div> <div> Examples are Rohu, Carps, sharks, electric rays</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 117</div> <div> An ornamental fish</div> <div> Amphibians</div> <div> Are transition between aquatic and land animals</div> <div> Gills, lungs and cutaneous respiration</div> <div> 5 chambered double circuit heart, mixing of blood</div> <div> Some part of the life is aquatic and some part terrestrial</div> <div> Produce large number of eggs, no parental care</div> <div> Ectotherms</div> <div> Examples are frogs, toads</div> <div> A frog</div> <div> Reptiles</div> <div> Of diverse types, widely distributed, aquatic and marine</div> <div> Highly adapted for hot dry habitats such as deserts</div> <div> Terrestrial animals, ectotherms</div> <div> Scaly skin, four chambered double circuit heart</div> <div> Lungs for gas exchange</div> <div> e.g. lizards, chameleon, turtles, tortoises, crocodiles, snakes, gavials</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 118</div> <div> An alligator</div> <div> Birds</div> <div> Arial mode of life, terrestrial life, fore arms modified into wings</div> <div> Endotherms, 4 chambered heart</div> <div> Lungs and air sacs for respiration</div> <div> Lays fewer eggs, provide parental care</div> <div> Bones light weight called hollow bones</div> <div> Grain eaters to omnivores</div> <div> e.g. parrots, pigeons, peacock, pelican, king fisher</div> <div> A type of crane</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 119</div> <div> Mammals</div> <div> Widely distributed, most complex, endotherms</div> <div> 4 chambered heart, lungs for gas exchange</div> <div> Highly developed brains</div> <div> Young ones are born mostly, mother feed them with milk, provide parental care</div> <div> Have hairs on their body, provide insulation</div> <div> Thick skin with skin sensory receptors</div> <div> Heterotrophs, herbivores to omnivores</div> <div> A rhinoceros</div> <div> Importance of Vertebrates</div> <div> These are beneficial</div> <div> Important parts of food chain and webs</div> <div> Beauty and diversity of nature</div> <div> Provides protein foods to human beings, eggs, milk, meat, honey</div> <div> Furs and feathers are used for various purposes</div> <div> By products of fish industry</div> <div> Pearls, clam culture</div> <div> Lac insect and silk worm</div> <div> Snake venom for medicines</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 120</div> <div> These are harmful</div> <div> Poisonous animals, e.g. frogs, snakes,</div> <div> Parasitic animals, e.g. worms, mites, ticks</div> <div> Insect pests of crops</div> <div> Other animal pests e.g. rats</div> <div> Termites damage woody structures of buildings</div> <div> Exercise</div> <div> 1. How biology helps in dealing with parasites?</div> <div> 2. How can we use knowledge of biology to improve our animal keeping capability?</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 121</div> <div> Biology lecture # 17</div> <div> Applications of Biology</div> <div> Biology – Useful for Humankind and World</div> <div> · Demands and problems are increasing with increase in population.</div> <div> · Biologists investigate phenomena of nature and problem and find ways to resolve these.</div> <div> · They introduced techniques and technologies to explore all biological resources to cope</div> <div> demands and resolve problems.</div> <div> Biotechnology</div> <div> · Biotechnology is the use and manipulation of biological processes, organisms and</div> <div> systems to manufacture products to improve the quality of human life.</div> <div> · The term biotechnology was first used in 1970’s.</div> <div> · Some important applications</div> <div> Genetic Engineering</div> <div> Fermentation and Microorganisms</div> <div> Genetic Engineering</div> <div> · It is a process in which a useful gene is taken from one organism and inserted into</div> <div> another organism. The resulting organism is called transgenic.</div> <div> · This process is carried out with the help of vectors and enzymes.</div> <div> · Most common vector is bacterial plasmid.</div> <div> · Most common enzymes are restriction endonucleases or restriction enzymes.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 122</div> <div> The Process of Genetic Engineering: Transgenic organisms (organisms that acquires a</div> <div> foreign gene)</div> <div> Transgenic bacteria</div> <div> o E. coli – most commons microorganisms in biotechnology because these have</div> <div> many strains (types) which are non-pathogenic, i.e., these cannot produce</div> <div> disease.</div> <div> o GRAS (Generally regarded as Safe) Organisms are those which are known for</div> <div> their non-pathogenecity.</div> <div> o Chemical industry: Acids and alcohols are produced using bacteria.</div> <div> o Pharmaceutical industry</div> <div> o Formation of insulin by E. coli for diabetic patients</div> <div> o Formation of human growth hormone for dwarf children</div> <div> o Formation of vaccines</div> <div> Transgenic Bacteria</div> <div> Transgenic bacteria are used in many industries, for example:</div> <div> o Food industry</div> <div> o Yogurt, Cheese, Sour creams are prepared using microorganisms</div> <div> o Breads b use of yeast</div> <div> o Beverages, drinks by yeasts or some bacteria</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 123</div> <div> o Treatment of waste materials is also carried out using different form of bacteria</div> <div> or even yeast. The microorganisms are used to treat:</div> <div> o Solid wastes</div> <div> o Waste water</div> <div> o Oil spills</div> <div> o Nuclear wastes</div> <div> o Bacteria and algae are also helpful in biofuels production (biogas, biodiesel etc).</div> <div> Transgenic plants</div> <div> These plants are produced to develop certain specific properties in these, for example, resistance to</div> <div> viruses. Some examples are following:</div> <div> o Virus resistant crops (cotton)</div> <div> o Insect resistant corn</div> <div> o Genetically modified banana</div> <div> o Pesticide resistant crops</div> <div> o FOOD SAFETY AND SECURITY: This is very important in modifying food</div> <div> crops particularly that if we are inserting a gene of resistance or else, the plant</div> <div> should not develop any harmful characteristic. For this purpose, before selling</div> <div> any transgenic seed or other product to market, it is tested for safety. This is</div> <div> called biosafety.</div> <div> Transgenic animals</div> <div> o Transgenic mice as model of human disease</div> <div> o Obese rats, diabetic mice</div> <div> o Genetically modified organisms to increase milk yield</div> <div> o Genetically modified farm animals to produce antibodies</div> <div> o FOOD SAFETY AND SECURITY: This is very important in modifying food</div> <div> producing animals particularly that if we are inserting a gene of interest the</div> <div> animal should not develop any harmful characteristic. For this purpose, before</div> <div> selling any transgenic product to market, it is tested for safety. This is called</div> <div> biosafety.</div> <div> Fermentation Pathways</div> <div> Microorganisms carryout fermentation, i.e., utilization of anaerobic pathway for production</div> <div> of energy. They produce many useful products for us during these pathways. These products</div> <div> are commercially produced by growing such organism in mass culture in very big vessels</div> <div> called fermenters or bioreactors.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 124</div> <div> Following products are obtained by this process:</div> <div> · Biofuels</div> <div> · Acids and alcohols</div> <div> · Yogurt, cheese, sour creams</div> <div> · Bread</div> <div> · Beer, wine</div> <div> Applications of biology in culturing Animal</div> <div> Animals are traditionally cultured for their products</div> <div> · Meat from fish, chicken, goats, cows</div> <div> · Milk from cows, buffaloes</div> <div> · Eggs from hens, ducks</div> <div> · Wool from sheep</div> <div> · Leather industry uses skins</div> <div> · Honey from Honey bee</div> <div> · Silk from silk worm</div> <div> Poultry farms provide us with meat and eggs.</div> <div> Common types of animal cultures</div> <div> Aquaculture</div> <div> Ornamental fish</div> <div> Seri culture (Silk worm)</div> <div> Dairy and Poultry</div> <div> Apiculture (honey bee)</div> <div> Biological pest control</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 125</div> <div> We discuss these one by one briefly.</div> <div> Aquaculture</div> <div> Culturing animals in water is called aquaculture for example fish farming.</div> <div> · Fish farming, Prawn culture</div> <div> · Pearl oyster culture</div> <div> · Other aquacultures (clams, lobsters etc.)</div> <div> · Byproducts of fishing industry include many cosmetics and some animal diets.</div> <div> Biology helps in improvement of fish varieties and also extraction of various products from</div> <div> these, for example:</div> <div> Selection of fishes in a fish pond (herbivores, carnivores)</div> <div> Feed for fishes which may increase their production</div> <div> Diseases and their treatment: biology help in finding causes of diseases and their</div> <div> treatments.</div> <div> Aquaculture for Ornamental Fish</div> <div> Ornamental fishes are the beautiful usually small fishes kept in small aquaria in houses or</div> <div> other places like hotels. Biology helps in:</div> <div> Feed: which is good for their maintenance</div> <div> Diseases: how can we handle diseases</div> <div> Requirements for healthy culture in small to large aquaria</div> <div> We keep aquaria at home</div> <div> Sericulture</div> <div> Culture of silk moth for making silk on mulberry leaves is called sericulture. It is a popular</div> <div> home industry in many parts of the world</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 126</div> <div> Biology helps in improvement of this culture:</div> <div> Process of making silk</div> <div> Diseases in moth or larvae can result in huge loss</div> <div> Biology helps in making new varieties, e.g., wingless variety, varieties which</div> <div> completes 5-6 cycles in a year</div> <div> Sericulture, a cocoon on the leaf of mulberry</div> <div> Dairy and poultry</div> <div> Biology plays very important roles in dairy and poultry industries. Biology helps in many</div> <div> ways for example:</div> <div> · Improved breeding techniques and cross breeds (more vigorous and resistant).</div> <div> · Improved quality and quantity yield of meat, milk, wool and eggs.</div> <div> · Diagnosis and cure for diseases in farm animals.</div> <div> · Biological knowledge is also helping in providing balanced food for best yield.</div> <div> Apiculture (honey bee)</div> <div> Keeping the honey bee for honey production is called Apiculture (Bee keeping). Biologists</div> <div> explore the phenomena behind Honey production, like knowledge of biology tells us that:</div> <div> Honey bee is a social insect and lives in large colonies</div> <div> Queen bee, drones and workers</div> <div> Biology helps in understanding how this system works and can help in production of better</div> <div> varieties and improved system for culturing these animals to increase yield of honey.</div> <div> Cocoon</div> <div> Mulberry leaf</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 127</div> <div> Honey bee (small sized) Honey bee (large sized)</div> <div> A unit of honey bee keeping farm</div> <div> Biological pest control</div> <div> A large number of organisms damage the useful plants or animals and can cause huge losses.</div> <div> These are called pests, e.g., many insects damage crops.</div> <div> There are few ways to control pests:</div> <div> Primary or cultural control</div> <div> o Crop rotation rather than monoculture, i.e., different crops are grown at different</div> <div> seasons.</div> <div> Chemical control</div> <div> o Various chemicals are used to kill insects but insects may develop resistance and</div> <div> chemicals are dangerous for health</div> <div> · Biological control means that the pests are controlled or killed by living organisms.</div> <div> Man’s head is covered</div> <div> while handling bees.</div> <div> Man’s hands are also covered.</div> <div> ©Copy right Virtual University of Pakistan</div> <div> 128</div> <div> o This is the most promising method of pest control</div> <div> o The natural enemies and predators of the pests are used to kill the pests</div> <div> o Lady beetles for citrus fruits</div> <div> o Bacillus thuringienesis for cotton</div> <div> Selection of biological control agent needs care. These should be ecologically safe. For</div> <div> example if we introduce a sparrow for eating an insect and that sparrow also start eating some</div> <div> plants. This will be even more harmful for crops and environment.</div> <div> Advantages of biological pest control</div> <div> They do not pollute the environment.</div> <div> They do not disturb the natural ecosystem.</div> <div> A more permanent control because pest usually do not develop resistance</div> <div> Applications of Biology in agriculture and plant growth</div> <div> Plants are in many ways useful</div> <div> · Parts of ecosystems, producers</div> <div> · Food crops: crops, which makes our food like wheat, rice, vegetables.</div> <div> · Many useful products like perfumes, medicines, furniture</div> <div> · Beauty of the nature, ornamental plants</div> <div> Biology helps in:</div> <div> · Understanding the life cycles and methods of spread</div> <div> · Better varieties by cross breeding or genetic engineering</div> <div> · Disease mechanisms and control</div> <div> · Appropriate soil, fertilizers and water availability</div> <div> Exercise</div> <div> 1. Discuss the role of biology in apiculture.</div> <div> 2. Describe the process of sericulture.</div> <div> 3. What are important advantages of biocontrol?</div> </div> <div> <br /></div> <div> <a href="http://www.genrica.com/vustuff/BIO101/BIO101_handouts_1_17.pdf" target="_blank"><b>Basic I-Biology (BIO101) book HANDOUTS / POWER POINT SLIDES in pdf</b></a></div>

Basic I-Biology (BIO101) book HANDOUTS / POWER POINT SLIDES in pdf

Basic I-Biology (BIO101) book HANDOUTS / POWER POINT SLIDES in pdf Handouts | Lectures | Contents | Books Biology lecture # 1 ...

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