Module 6

1. Photosynthesis is the process of converting light energy into chemical energy (glucose).
2. Chlorophyll-a is the primary pigment involved in photosynthesis.
3. C4 plants show higher photosynthetic efficiency at high temperature and light.
4. CAM plants fix CO₂ at night using PEP carboxylase.
5. Photorespiration occurs only in C3 plants.
6. Calvin cycle takes place in the stroma of chloroplasts.
7. Light reaction occurs in the thylakoid membrane.
8. Kranz anatomy is characteristic of C4 plants (e.g., maize, sorghum).
9. CO₂ compensation point is lowest in C4 plants.
10. Rubisco is both a carboxylase and oxygenase enzyme.
11. Stomatal opening is controlled by K⁺ ion movement in guard cells.
12. Transpiration helps in cooling and nutrient transport.
13. Wilting occurs when transpiration exceeds water absorption.
14. Water potential (Ψw) is the potential energy of water in a system.
15. Turgor pressure maintains plant rigidity.
16. Osmosis is movement of water from low solute to high solute concentration.
17. Diffusion pressure deficit (DPD) drives water movement in plants.
18. Guttation occurs through hydathodes during high soil moisture.
19. Imbibition is the absorption of water by colloids like starch and protein.
20. Transpiration ratio = water lost / dry matter produced.
21. Photoperiodism is response of plants to length of day and night.
22. Short-day plants flower when day length is less than critical period.
23. Long-day plants flower when day length exceeds critical period.
24. Vernalization is induction of flowering by low temperature.
25. Phytochrome is the photoreceptor controlling photoperiodism.
26. Phytochrome exists in two forms: Pr and Pfr.
27. Phototropism is growth response to light direction.
28. Geotropism is growth response to gravity.
29. Auxins promote cell elongation and apical dominance.
30. Cytokinins promote cell division and delay senescence.
31. Gibberellins promote stem elongation and seed germination.
32. Abscisic acid (ABA) induces dormancy and closes stomata.
33. Ethylene promotes fruit ripening and leaf abscission.
34. Plant growth regulators (PGRs) are organic compounds influencing growth.
35. Bolting in cabbage and onion is due to gibberellins.
36. Parthenocarpy (seedless fruit) is induced by auxins.
37. Apical dominance is controlled by auxin–cytokinin balance.
38. Senescence is delayed by cytokinins.
39. Translocation of food occurs through phloem.
40. Source is the photosynthesizing organ; sink is the storage organ.
41. Phloem loading involves active transport of sucrose.
42. Respiration releases energy by oxidation of glucose.
43. Glycolysis occurs in cytoplasm.
44. Krebs cycle occurs in mitochondrial matrix.
45. Electron transport chain (ETC) occurs in mitochondrial membrane.
46. ATP is the universal energy currency of the cell.
47. Respiratory quotient (RQ) = CO₂ evolved / O₂ consumed.
48. RQ for carbohydrates = 1, for fats < 1, for organic acids > 1.
49. Photorespiration reduces photosynthetic efficiency.
50. CAM metabolism conserves water in arid plants.
51. Assimilation rate depends on leaf age and light intensity.
52. Net photosynthetic rate = Gross photosynthesis – Respiration.
53. Crop growth rate (CGR) = (W₂ – W₁) / (t₂ – t₁).
54. Relative growth rate (RGR) = (ln W₂ – ln W₁) / (t₂ – t₁).
55. Leaf Area Index (LAI) = Leaf area / Ground area.
56. Harvest index (HI) = Economic yield / Biological yield × 100.
57. Translocation of photosynthates is active and energy-dependent.
58. Source–sink relationship determines yield.
59. Drought resistance is associated with low transpiration and deep roots.
60. Heat stress affects photosystem II activity.
61. Chilling injury occurs in tropical crops below 10°C.
62. Oxidative stress is due to reactive oxygen species (ROS).
63. Proline accumulation helps osmotic adjustment in stress.
64. Antitranspirants reduce water loss through stomata.
65. Hydrogen cyanamide breaks seed and bud dormancy.
66. ABA accumulates under water stress conditions.
67. Cytokinin to auxin ratio determines root vs. shoot growth.
68. Senescence begins in older leaves first (source exhaustion).
69. Mineral nutrients affect enzyme activity and metabolism.
70. Nitrogen promotes vegetative growth.