Metabolism of Amino Acids and Nucleotides — DU B. Sc. (Hons) Biochemistry Previous Year Question Papers

There äre six questions in all. Attémpt four questions in all. 1. (A) Explain the following : (a) Serine can be synthesized from glycolytic intermediates. (b) The only methyl group transfer that does not involve SAM is the synthesis of Methionine itself. (c) Isoleucine and valine metabölism is affected by Vitamin B12 (f) Aspartate aminotransferase has the highest activity of all the mammalian liver aminotransferases. (B) Give one significant contribution of the following scientists: (b) Archibald Garrod (c) John Buchanan. 12,3 2. (A). Outline the de-novo pathway of purine biosynthesis. Explain the Gamma glutamyl cycle. 5,6,4 3. (A) Write the reaction for the following conversions: (b) Methionine to cysteine (c) Arginine to creatine (d). Phenylalanine to Homogentisate. (B) Regulation of glutamine synthetase is the primary point in bacterial nitrogen metabolism. Elaborate. 10,5 4. (A) Describe the mechanism of action of the following drugs : (a) N-acetyl glutamate (B) Explain the pathway for the catabolism of purine nucleotides into uric acid. (C) Discuss the regulation of urea cycle. 8,4,3 (A) Write any two reactions of amino acid metabolism where PLP is involved as a coenzyme. (b) Maple syrup urine disease 6. (A) Describe the following in brief: (i). Kreb's Bicycle (ii) Glycine cleavage system. (B) How is Ribonucleotide reductase regulated? (C) Differentiate between the Carbamoyl phosphate synthetase I and II. 6,5,4