Biochemistry — DU B. Sc. (Hons) Biomedical Previous Year Question Papers

(a) Calculate the energetics of complete oxidation of one acetyl-CoA molecule in the TCA cycle. (b). The HMP pathway is very important in the RBCs. Explain why? (d) Explain why a deficiency in urea cycle enzyme(s) results in hyperammonaemia and what dietary adjustment might minimise the associated toxicity. (d) Gel Filtration Chromatography determines the molecular weight of a protein to be 300 Explain this observation and discuss the principle of SDS-PAGE. (c) Give illustrations, biochemical reactions, and examples wherever required. 1. (a) Justify the following statements: (i) Palmitic acid undergoes 7 rounds of B-oxidation to yield 8 molecules of Acetyl (ii) PFK-1 is the key regulatory enzyme in glycolysis. (ill) Beer's law is disobeyed at high concentrations of molecules. (iv) Enzymes catalyse biochemical eactions by lowering the activation energy. (v) Oligomycin inhibits ATP synthesis. (vi) Oxidation of FADH, yields less energy than that obtained from NADH. (b) Define the following: 1.5x4=6 (ii) Anaplerotic reactions (iii) Isoelectric point (pl) 2. Differentiate between the following (any three): (i) Hyperbolic & Sigmoidal Enzyme Kinetics (i) Cori's cycle & the Glucose-Alanine cycle (iV) Oxidative & Non-oxidative phase of HMP 3. Write short notes on the following (any three (i) Oxidative phosphorylation. (ii) Ketone bodies (il) Beta-oxidation of fatty acids (iv) Regulatory enzymes 4. Give complete biochemical reactions catalysed by the following enzymes: (ii) Succinate Dehydrogenase (iv) Pyruvate carboxylase (v) Lactate dehydrogenase (vi) IMP dehydrogenase 5. (a) Explain the principle and applications of spectrophotometry in biomolecule analysis. 6 (b) Giving any two biochemical reactions, describe the role of NADH and ATP as metabolic regulators. (c) Why have we evolved to metabolise glucose under anaerobic conditions also? Explain the regulation and significance of glycolysis.