Basic concepts of Biomolecules — DU B.Sc. (Hons) Biological Sciences Previous Year Question Papers

Attempt four questions in all. 1, i) Discuss the structure, classification, and properties of common fatty acids. (i) Predict the number of stereoisomers possible for tartaric acid and classify them. Explain the erythro/threo and D/L systems-of configuration, with "sit in suitable example. 1- lee i -7.5×2=15 2. (i) Explain how inductive, resonance, and hyperconjugation effects influence the stability of carbocations. (i) Explain the concept, of dipole, moment. How can dipole moment data be used to distinguish between cis and trans isomers,? Take suitable example for the explanation. (iti) Define hydrogen bonding. Differentiate between intermolecular and = 300 7, $ Fun ali atti intramolecular hydrogen bonding and their significance in biomolecular stability. +3. (i) Discuss the importance of stereochemistry in biological systems with we suitable examples of biomolecules and also describe how"chirality affects the pharmacological activity of drugs with suitable examples. (i) Describe the cis-trans isomerism involved in the visual process (retinal and rhodopsin system). (iti) Assign E/Z or R/S : 5×3=15 Was i COOH: ! 13 4. (i). What, is the role of enzymes in catalyzing organic reactions in biological systems ? Whịch: enzyme catalyzes the retro aldol cleavage of fructose-1, 6-bisphosphate in glycolysis? Give reaction... (it) Illustrate the stepwise mechanism of TPP-mediated benzoin condensation during acetyl-CoA formation. (iii. Write the reaction, mechamism of conversion between pyruvate and 21-i i lactate, indicating the cofactors involved (NADH/NADt). Name the enzyme that converts glucose-6-phosphate to fructose-6-phosphate. 5×3=15 5. (i) Explain the types of glycosidic linkages found in di- and polysaccharides with examples: (i). Explain the reactions of glucose with : (a) Fehling's solution (6) Tollen's reagent - (c) Bromine water. - (iii) Write short notes on : (b) Haworth projection formulae. 5×3=15 6. (i). Discuss the structure and biological importance of phospholipids. (it) Describe the 'charactéristics' of fats and oils and explain ? (a) Saponification' value :' 16) Iodine value ... ". ' (c) Acid value. (iii) Discuss the structure and role of essential fatty acids in biological