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

Attempt.five questions in all, Attempt sub-parts of questions together: . • "Give example and illustrations and Chemical structures whèrever required. 1." (a) Define (any four)": "': (" Semi-essential amino acid " "" 'uta" (il) Resolution, of Racemic modification (b) Diferentiate (any three) : j.. (i) Reducing sugar and Non-reducing sugar (ii) Starch and Cellulose (iv) D and d configuration. (e) Give the structure of the föllowing (any five) : 5x2=10 (i) Dipeptide structure of "Gly-Ala" (ii) Haworth projection of D-Mannose (Et) Linoleic "acid (vi) Meso compound: 1 : ! =* 4 = ** 2 2. (a) Discuss Acid-Base properties of, glycine by providing appropriate reactions. Graphically explain the change in concentration of the different molecular species with change in pH. (b) Cyclohexane can exhibit both conformational and geometrical isomerism. Explain the observation taking 1,:4 dimethyl cyclohexane as the example. : 3. (a) The absorption spectrum of nucleic acid has a peak at 260 nm. Explain. (6) The polarimetric study of a mixture containing two enantiomers showed that it wäs optically inactive. Another mixture prepared using the same set of enantiomers was found to be optically active. Explain the observation with suitable example. (e) The melting point is much lower for cis-fatty acids compared to trans and saturated fatty acids. Explain with suitable diagrams. 5,5,5 (a) Give structure of maltose and explain why it is a reducing sugar. (b) What is a B-turn? Certain amino acids promote' formation of B-turns, explain giving structures of amino acid involved." (e) Lipids are molecules of choice for storage of metabolic energy. Comment. Giving reaction mechanism and biological relevance of the following reaction (any three) : 5,5,5 (a) Cannizzaro reaction (b) Retro aldol (c) Claisen condensation 6. (a) Give the structure of threo 2, 3 dibromo butyraldehyde! Convert it into : Newman projection form. (6) Assigning priority order 'and assign E/Z or R/S configuration to each of • F the following;