Plant Physiology and Metabolism LS-BOT-DSC 05 — DU B. Sc. Life Science (Botany) Previous Year Question Papers

5. Answer all parts of a question together. (a) Expand the following (any five) : (1x5=5) (iii) ROS (b) Define the following (any five) : (1x5=5) (il) Solute potential (ill) Apical dominance (c) Give one word for each of the following (any five): (1x5=5) (1) The metabolic pathway converting glucose to pyruvate. (i) The enzyme catalyzing biological nitrogen fixation. (ili) Plant hormone inducing stomatal closure during water stress. (iv) Process of chilling treatment for early flowering. (v) An antioxidant enzyme. (vi) An oxygen-scavenging protein present in the root nodule. 2. Differentiate between the following (any five) : (a) Photosystem I and II (c) C3 and C4 cycle (d) Macro- and micro nutrients (f) Phloem loading and unloading 3. Write short notes on the following (any three) : (a) Cyanide-resistant respiration (b) Induction of seed germination by gibberellin (molecular mechanism) (c) Root pressure theory (d) CAM-pathway 4. (a) Explain the general roles of essential elements. Describe the role of iron, molybdenum, manganese, and potassium. (3+4=7) (b) Define transpiration and describe its significance. Explain internal and external factors affecting transpiration. (1+3+4=8) 5. (a) Describe structure of enzyme. Explain the mechanism of enzyme action. (3+4=7) (b) Illustrate the basic structure of nitrate reductase (NR) and nitrite reductase (NiR), and explain their role in the assimilation of nitrate to ammonia.