LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PLANT BIOLOGY & PLANT BIO-TECH.
FIFTH SEMESTER – APRIL 2012
PB 5515/PB 5509/PB 5500 - PLANT PHYSIOLOGY
Date : 25-04-2012
Time : 9:00 - 12:00
Dept. No.
Max. : 100 Marks
PART A
Answer the following, each in about 50 words:
(10 x 2 = 20 marks)
1. Define the second law of thermodynamics.
2. Comment on antitranspirant.
3. What is an essential element?
4. Define Donnan’s equilibrium.
5. What are CAM plants?
6. What do you mean by photo synthetic phosphorylation?
7. Define the chemiosmotic hypothesis.
8. Define cellular oxidation.
9. What is water stress?
10. Define the term ‘dormanul’.
PART B
Answer the following, each within 500 words;
Draw diagrams wherever necessary:
(5x7=35 marks)
11. a) Define water potential. Explain its components and bring out their relationships.
(OR)
b) Explain how K+ ions regulate the opening and closing of stomata.
12. a) What is active absorption of mineral ions? Explain any one concept of active absorption
of mineral ions.
(OR)
b) What is passive absorption of mineral ions? Explain any one concept for passive
absorption of mineral ions.
13. a) Schematically represent the photorespiration, explain the important steps and the
significance of photorespiration.
(OR)
b) Schematically represent the light reaction and mention its importance.
14. a) Explain the mechanism of biological nitrogen fixation.
(OR)
b) Explain the various sources of nitrogen and the synthesis of amino acids.
15. a) What is bioassay? Explain any one bioassay for auxin and any one for gibberellins.
(OR)
b) Discuss the physiological roles of ethylene.
PART C
Answer any THREE of the following, each within 1200 words only;
Draw diagrams and flowcharts wherever necessary:
(3x15=45 marks)
16. Describe the path of water from the soil to the atmosphere.
17. Describe the function, deficiency symptoms and remedial measures of any four macro and
any four micro nutrients.
18. Explain how CO2 is fixed in a C3 plant. Bring out the differences between C3 and C4 plants.
19. Explain the oxidation of glucose molecule by aerobic respiration.
20. Write an essay on physiology of flowering.
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