Biochem 323-internal 2005

Universal Science College (B. Sc. Biochemistry) Sixth Semester 2005

Internal Examination Subject: Biochem 323 (Plant Biochemistry) Date: July 28, 2005

Full Marks: 100 Pass Marks: 45 Time: 3 hours

Candidates are required to give their answers in their own words as far as practicable. The figure in the margin indicates full marks. Group (A) Long Questions (Any three) (3× ×14 = 42) 1. Explain and illustrate structure and function of plant Lipids and their constituent fatty acids. Compare chloroplastic lipids with extra chloroplastic lipids. 2. Describe the pathways of cyclic and non-cyclic photophosphorylation. Explain how ATP synthase works. 3. Describe the process of biological nitrogen fixation in legumes. How is nitrogenase enzyme regulated in the process ? 4. How are the chalcones synthesized in plants? Draw structure of flavone, isoflavones, leucoanthocyanidins, dihydroflavonol and flavonol. Group (B) Short Questions: (Any six) (6× ×7 = 42) 1. Describe with mechanism beta – oxidation. 2. Describe the strategies for genetic manipulation for enhancing cold tolerance in plants. 3 What reactions are involved in Calvin cycle? How is Rubisco regulated ? 4 Describe the process of photorespiration. How is it avoided by C4 plants ? 5 Describe the structure and function of nitrogenase enzyme. 6 Describe the role of aminotransferase in nitrogen metabolism. 7 What is Abscisic acid? How is Mevalonic acid converted to Abscisicacid? 8 Draw general pathway for the formation of monoterpenoids from hydroxymethylglutaryl CoA (HMG-C0A). Group (C) Write short notes on: (Any eight) (2× ×8 = 16) 1. Alpha- oxidation 2. Fatty acid elongation 3. Suberin 4. Action spectrum 5. Emerson enhancement effect 6. Photolysis of water 7. CAM plants 8. Heterocyst 9. Urea cycle 10. Draw the basic structure of three naturally occurring quinines 11. Name the aminoacid which gives tropane alkalods(hyoscymine and Nicotine) and write scientific name of plants where they occur. 12 What is the role of delta-1-prophenylsulfenic acid and syn-propanethoil S-oxide in Allium genus? ***