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*PG961*

PG – 961

I Semester M.Sc. Degree Examination, January 2015 (Semester New Scheme) BIOCHEMISTRY BC-101 : Fundamentals of Chemistry and Environmental Biochemistry Time : 3 Hours

Max. Marks : 80

Instruction : Answer question no. 1 and any five of the remaining. 1. Answer any ten of the following :

(10×2=20)

a) What are buffers ? Give an example for a biological buffer. b) Give the biological importance of water. c) Differentiate between enantiomers and diastereomers. d) What are structural isomers ? Give an example. e) What are valence electrons ? f) State Hammond’s postulate. g) What are reactive intermediates ? Give an example. h) Give the hydrolysis products of a typical amide and an ester. i) Give the structure of isoalloxazine. j) What are ligand replacement reactions ? Give an example. k) Define LD50 ? l) What is food toxicity ? Give an example. 2. a) Give a detailed account on the bonding in biological molecules. b) What is absolute configuration ? Discuss Cahn-Ingold-Prelog priority rules in determining R and S configuration of chiral compounds by taking lactic acid as an example. (6+6=12)

P.T.O.

*PG961*

PG – 961

3. a) Discuss the mechanism of aldol condensation with a suitable example. b) Discuss the mechanism of base catalyzed ester hydrolysis.

(6+6=12)

4. a) By taking a suitable example discuss the mechanism of Wagner-Meerwein rearrangement. b) Discuss the mechanism of nucleophilic substitution reaction in a primary alkyl halide and explain why it follows SN2 mechanism.

(6+6=12)

5. a) Explain the salient features of Ligand Field Theory of metal complexes. b) Explain the formation of transition of metal complexes.

(6+6=12)

6. a) Discuss the factors affecting the toxicity of a chemical. b) How is hepato-toxicity of a chemical toxicant determined ? c) Give the structure and biological significance of imidazole. 7. Write notes on any three of the following : a) Bioremediation of toxicants. b) Baeyer-Villiger oxidation of ketones. c) Beckman Rearrangement. d) Dose-response relationship of toxicants.

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(4+4+4=12) (4×3=12)