Biology, Chemical and Cellular Foundations of Life - Assignment Example

No. Answers a. C. Cells from a plant leaf b. It is larger in size compared to the others. C Organelle Y is Mitochondria, known as "power house"of the cells, functions in providing energy production. C.2. Organelle Z is Endoplasmic reticulum and has function of protein maturation, post-translational modification and provides support to ribosome and protein transport. d. Mitochondria possess size ranging from 0.5 micrometer (0.00005 in) to 1 micrometer (0.0001 in) in length. Therefore, it cannot be viewed under an ordinary microscope due to its limitation in resolving power. Electron microscopes have much greater resolving power than light microscopes and can obtain much higher magnifications. 2.a.i. A = Lipid layer B = Integral protein C = Transmembrane channels D = Oligosaccharide E = Glycolipid ii. 7nm b.i. Y. ii. In the diagram the glycoproteins and the glycolipids are on the X side, which is the cell surface side since, glycoproteins and glycolipids are cell surface receptors and also plays a role in cell adhesion. Thus, the Y side is cytoplasm of the cell. C. Integralproteins or transmembrane proteins- Span the membrane and have a hydrophilic cytosolic domain which interacts with internal molecules, a hydrophobic membrane-spanning domain which anchors it within the cell membrane, and a hydrophilic extracellular domain which interacts with external molecules. The hydrophobic domain consists of one, multiple, or a combination of -helices and sheet protein motifs. Glycoproteins - glycoproteins and glycolipids are cell surface receptors and also plays a role in cell adhesion. Transmembrane channels - Transport of nutrients, ions and molecules in and out of the cell. d. Most of the biological molecules are either larger in size or having definite charges on it. Hence The plasma membrane is non permeable to it. lipid bilayer is permeable only to water molecules and a few other small, uncharged, molecules like oxygen (O2) and carbon dioxide (CO2). These diffuse freely in and out of the cell. e. Passive transport involves carriers, channels, or direct diffusion through a membrane. This type of transport always operates from regions of greater concentration to regions of lesser concentration. No external source of energy is required, thus "passive" whereas in In active transport it is possible to go against the concentration gradient and an external source of energy like ATP is required to move the carrier and its materials thus, "active" 3a i A. Connective tissue B. Ciliated epithelium C. Columnar epithelium ii A. Connective tissue joints bone with muscles B. Ciliated epithelium forms lining of the respiratory systems C. Columnar epithelium forms lining of the digestive track. B i and ii The primary function of Connective tissues is to connect and join different organs. Ciliated epithelium tissue has cilia which helps cleaning the surface and restrict settlement of microorganism on to the surface. Columnar epithelium having a appendages called microvilli which helps in smooth movement of food particles in intestine. 4.a. Ribbon shape structure. b. It is a linear chain of amino acids. C.i. X- beta sheets Y-alpha helix ii. Hydrogen bonds d. Tertiary structure is responsible for formation of active site for lysozyme, the site responsible for the enzyme catalysis. 5.a. i-D ii-E iii-A iv-B v-C b. i. Glucose ii.a triglycride iii. an amino acid Simple sugar has aldehyde and ketone whereas Triglyceride contains fatty acids and glycerol . Amino acids possess carboxyl and amino groups. c. Uracil is present in RNA whereas Thymine is present in DNA. 6.a. Mitosis and Meiosis. b. Growth= Mitosis Reproduction = Meiosis C During fertilization two cells are combine and forms zygot. Number of chromosome should be maintain 2n and that's why It is necessary for reduce chromosome number to n fro 2n during gamete formation. 7a G1 phase, S or synthesis phase, and G2 phase. b. G1 phase: The first phase within interphase, from the end of the previous M phase till the beginning of DNA synthesis is called G1 (G indicating gap or growth). During this phase the biosynthetic activities of the cell, which had been considerably slowed down during M phase, resume at a high rate. This phase is marked by synthesis of various enzymes that are required in S phase. S or synthesis Phase: The ensuing S phase starts when DNA synthesis commences; when it is complete, all of the chromosomes have been replicated, i.e., each chromosome has two (sister) chromatids. Thus, during this phase, the amount of DNA in the cell has effectively doubled, though the ploidy of the cell remains the same. G2 phase :Cell then enters the G2 phase, which lasts until the cell enters mitosis. Again, significant protein synthesis occurs during this phase, mainly involving the production of microtubules, which are required during the process of mitosis. Inhibition of protein synthesis during G2 phase prevents the cell from undergoing mitosis. c. Interphase: The cell is engaged in metabolic activity and performing its prepare for mitosis (the next four phases that lead up to and include nuclear division). Chromosomes are not clearly discerned in the nucleus, although a dark spot called the nucleolus may be visible. The cell may contain a pair of centrioles (or microtubule organizing centers in plants) both of which are organizational sites for microtubules. Prophase: Chromatin in the nucleus begins to condense and becomes visible in the light microscope as chromosomes. The nucleolus disappears. Centrioles begin moving to opposite ends of the cell and fibers extend from the centromeres. Some fibers cross the cell to form the mitotic spindle. Metaphase: Spindle fibers align the chromosomes along the middle of the cell nucleus. This line is referred to as the metaphase plate. This organization helps to ensure that in the next phase, when the chromosomes are separated, each new nucleus will receive one copy of each chromosome. Anaphase: The paired chromosomes separate at the kinetochores and move to opposite sides of the cell. Motion results from a combination of kinetochore movement along the spindle microtubules and through the physical interaction of polar microtubules. Telophase: Chromatids arrive at opposite poles of cell, and new membranes form around the daughter nuclei. The chromosomes disperse and are no longer visible under the light microscope. The spindle fibers disperse, and cytokinesis or the partitioning of the cell may also begin during this stage. 8. Tissue: An aggregation of morphologically similar cells and associated intercellular matter acting together to perform one or more specific functions in the body. Organ: Organ is a group of tissues that perform a specific function or group of functions. Organ system: When two or more different organs that work together to provide a common function is known as organ system. 9.a Monera- Escherichia coli protista - Amoeba fungi- Yeast palntae- pisum sativum animalia- homosapiens b The basic difference between eukaryote and prokaryotes is eukaryotes have distinct Nucleus and membrane bound organelles like Mitochondria, while they are absent in prokaryotes. C Viruses are grouped under non living as it lacks complete cellular structure and can not multiply independently. It depends on host for its reproduction and multiplication. Read More