1. Which of the following statement is incorrect?
a) Rhizobium and frankia are free living bacteria of soil.
b) Rhizobium is rod shaped (Bacillus).
c) Root nodule of pulse are pink due to the presence of leg-haemoglobin.
d) Rhizobium and frankia can fix nitrogen as free living bacteria
Explanation: "Rhizobium and frankia can fix nitrogen as free living bacteria". This statement is incorrect.
2. Leg-haemoglobin means
a) Low grade haemoglobin
b) Luminous haemoglobin
c) Leguminous haemoglobin
d) Low level haemoglobin
Explanation: Leg-haemoglobin means Leguminous haemoglobin
3. The sequential stage for principal stages of nodule formation are
(1) Rhizobia multiply and colonies the surrounding roots.
(2) Rhizobia attached to epidermal and root hair cells.
(3) Root hair curl and bacteria invades root hair.
(4) Initiation of nodule formation in cortex.
(5) Infection thread is produced carrying bacteria to cortex.
(6) Bacteria released from thread into cells and causes their differentiation in specialized
nitrogen fixing cells.
(7) Nodule formed is establish, a direct vascular connection with the host for exchange of
nutrient.
a) I → VII → II → VI → III → V → IV
b) II → III → IV → I → VII → V → VI
c) VII → VI → IV → I → III → V → II
d) I → II → III → V → IV → VI → VII
Explanation: I → II → III → V → IV → VI → VII
4. Root nodule of leguminous plant contains
a) Nitrogenase
b) Leg-haemoglobin
c) Both (a) and (b)
d) none of these
Explanation: Root nodule of leguminous plant contains both Nitrogenase and Leg-haemoglobin
5.The enzyme nitrogenase is
a) Mo-Fe protein
b) Mo-Mn protein
c) Mn-Fe protein
d) Cu-Fe protein
Explanation: The enzyme nitrogenase is Mo-Fe protein
6. Which cells are divided for nodule formation?
a) Inner cortex
b) Pericycle
c) Endodermis
d) Both (a) and (b)
Explanation: Both (a) and (b)
7. For the production of 2 mol. \[NH_{3}\] how much ATP is required in biological nitrogen fixation
reaction (i. e., \[N_{2}\rightarrow 2NH_{3}\] )?
a) 4
b) 8
c) 16
d) 32
Explanation: 16
8. Nitrogenase requires ___________ condition for its activity.
a) Aerobic
b) Anaerobic
c) Ozonized environment
d) \[CO_{2}\]
Explanation: Nitrogenase requires anaerobic condition for its activity
9. Which of the following is incorrect about nitrogen fixation in nodule?
a) It is a high energy process.
b) Leg-haemoglobin acts as oxygen scavenger.
c) Mg is required as a cofactor for nitrogenase enzyme
d) This process uses atmospheric nitrogen but not atmospheric hydrogen directly.
Explanation: "Mg is required as a cofactor for nitrogenase enzyme". This is incorrect.
10. Fats of \[NH_{3}\] formed during biological nitrogen fixation is
a) \[NH_{3}\] protonated to form
b) The \[NH_4^+\] ion formed is used for reductive amination
c) Glutamic acid is formed under reductive amination to undergo transamination.
d) All of these
Explanation: All of these