KVPY Interview Important Questions Biology Part 1
Q: 1. What is a cell? What are its components?
Sol. Cell is a structural and functional unit of all living organisms. Its main components include nucleus, various cytoplasmic organelles such as mitochondria, plastids (in plant cells only), Golgi complex, endoplasmic reticulum, ribosomes, cytosol and plasma membrane
Q: 2. What is cell wall made up of?
So. Cell wall is a rigid, non-living structure made up of cellulose (unbranched polymer of glucose with glycosidic linkages) microfibrils. It also contains water, hemicellulose, pectic substances, lipids, and proteins in its matrix. Other ingredients include lignin, cutin, suberin, silica, minerals, waxes, tannins, resins and gums in variable amounts.
Q: 3 Which enzyme digests protein in the stomach?
Sol. Pepsin (in adults) and rennin (in infants).
Q: 4. What is the pH of gastric juice in the stomach?
Q: 5. Why is gastric juice acidic?
Sol. Due to the presence of HCl secreted by the oxyntic or parietal cells of gastric glands.
Q: 6. What are proteins made up of?
Sol. Proteins are structurally and functionally diverse group of heteropolymers consisting of 20 different types of amino acids linked to each other by peptide linkages.
Q: 7. What is the relation between protein and enzyme?
Sol. All enzymes(except RNA enzymes like ribozyme and ribonuclease P) are proteins but all proteins are not enzymes. Enzymes are functional proteins (generally globular) and are also known as biocatalysts as they catalyse various metabolic reactions.
Q: 8. What are the ‘Y’ –shaped structures that are related with immune system called?
Sol. They are called antibodies or Immunoglobulins. These are a class of glycoproteins produced by plasma cells which in turn are produced due to the mitotic proliferation of B cells in response to their exposure to non-self-antigen/s. they are classified into five categories i.e. They are known to neutralize antigens (among many others) and hence play an important role in immunity (inherent capacity of an organism to combat diseases).
Q: 9. Which organ is both an endocrine as well as an exocrine gland?
Sol. Pancreas is endocrine as well as exocrine gland. Such a gland is also known as heterocrine-gland.
Q: 10. What are the secretions of pancreas?
Sol. The exocrine secretions of pancreas include amylase, lipase, trypsinogen, chymotrypsinogen, procarboxy peptidases, proelastase and nucleases. The two major endocrine secretions (hormones) from pancreas are insulin and glucagon secreted, respectively, from á and â cells of the Islets Langerhans.
Q: 11. What is the function of insulin?
Sol. Insulin is a protein hormone secreted by â cells of pancreas, in response to high blood glucose levels (e.g. after a meal) monitored by the â cells themselves. It induces hypoglycemic effect by promoting uptake of glucose by various body tissue cells, glycogenesis, & lipogenesis and by preventing Glycogenolysis & lipolysis.
Q: 12. What happens in diabetes mellitus?
Sol. It is characterized by hyperglycemia either due hyposecretion of insulin or non-responsiveness of body tissue cells to insulin. The former is known as type I or juvenile diabetes mellitus while the latter is termed as type II or middle age onset diabetes mellitus. Its symptoms include polyuria, polydipsia and polyphagia (triad of diabetes mellitus).
Q: 13. What can we do to cure diabetes mellitus?
Sol. Diabetes mellitus is not curable but it can be controlled by the use of the following three measures:
(i) Administration of insulin or oral hypoglycemic drugs
(ii) Consumption of low carbohydrate diet and small frequent meals
(iii) Regular exercise
Q: 14. What type of bacterium is Escherichia coli?
Sol. Escherichia coliismotile, gram-negative, rod-shaped bacterium (Family- enterobacteriaceae) used most extensively in genetics and molecular biology. It is normal inhabitant of the large intestine of man
Q: 15. What are amino acids?
Sol. Amino acids are organic acids (with carboxylic group) having amino group, generally attached to á carbon or carbon next to the carboxylic group. The á carbon also bears variable hydrocarbon or alkyl group R and hydrogen. There are 20 types of amino acids (differing) in their R-groups) involved in protein synthesis.
Q: 16. Name two amino acids that have selenium
Sol. Selenocysteine and Selenocystine
Q: 17. Name some amino acids which have sulphur
Sol. Cysteine, Cystine and Methionine
Q: 18. What are and?
Sol. (HX is an acid) and is known as acidity constant of the acid and is a measure degree of ionization of the acid and hence its strength. Smaller is the value of stronger is the acid.
and is known as basicity constant of the base and is a measure of the degree of ionization of the base and hence its strength. Smaller is the value of , stronger is the base.
Q: 19. What is AIDS? What are its effects?
Sol. The word AIDS stands for Acquired immunodeficiency Syndrome. This means deficiency of immune system, acquired during the lifetime of an individual indicating that it is not a congenital disease. It is characterized by the presence of certain opportunistic infections such as Pneumocystis carinii, Mycobacterium bovisand tumors such as Kaposi’s sarcoma in addition to lymphadenopathy.
Q: 20. Which cells do HIV infect?
Sol. Human Immunodeficiency Virus (HIV) infects blood cells i.e. CD 4+ cells (helper T -cells).
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