JUNE – 2021
B. Sc. (IV Semester) Examination
BOTANY
Paper: BOT-241
(Plant Physiology)
Full Marks : 50
Pass Marks : 35%
Time : Two Hours
Note: (i) Answer all the questions.
(ii) The figures in the margin indicate full marks for the questions.
1. Write on/explain any five of the following:5x2= 10
(a) Plasmolysis
(b) How does phytochrome differ from other plant pigments?
(c) What are the requirements for a seed to germinate?
(d) Circadian rhythm
(e) Vernalization
(f) Proton pump
(g) Cyclic photophosphorylation
(h) CAM anatomy
2. Answer any four of the followings:4x5= 20
(a) Describe Cohesion-Tension Theory
(b) What are cytochromes, and how do they function in photosynthesis and respiration?
(c) What is the difference between dormancy and quiescence? How may dormancy be artificially broken?
(d) Describe various Nastic responses in plants
(e) Write characteristics of active uptake mechanisms for mineral nutrients of plants.
(f) Describe the mechanism of Cytokinin action.
3. Answer any two of the following: 2x10 = 20
(a) Compare the mechanisms of carbon fixation in C3, C4 and CAM plants.
(b) Explain why Krebs cycle is more efficient in terms of ATP synthesis than EMP pathway.
(c) What is Light reaction? Describe in detail the role of photosystems in this reaction.
(d) How do day-neutral and intermediate-day photoperiod plants differ in their requirements?
