During biological nitrogen fixation, inactivation of nitrogenase by oxygen poisoning is prevented by?

1. Leghaemoglobin

2. Xanthophylls

3. Carotene

4. Cytochrome

Which of the following enzyme is not operational in Rhizobium during free-living conditions?

1. Aldolase

2. Nitrogenase

3. Enolase

4. Mutase

The function of leghaemoglobin in the root nodules of legumes is 

(1) oxygen removal

(2) nodule differentiation

(3) expression of nif gene

(4) inhibition of nitrogenase activity

The function of leghemoglobin in the root nodules of legumes is:
1. oxygen removal
2. nodule differentiation
3. expression of nif gene
4. inhibition of nitrogenase activity

Reaction of N₂ fixation process is depicted below

$N_2+\left[A\right]+\left[B\right]+16<mspace\; width="1em"></mspace>ATP\to$
$2N{H}_3+\left[C\right]+16ADP+16<mspace\; width="1em"></mspace>Pi$

Select the correct set of A,B and C

1. A = $8{\mathrm{e}}^{-}$, B=$8{\mathrm{H}}^{+}$; C = ${\mathrm{H}}_2$

2.  A = ${\mathrm{H}}_2$, B=$8{\mathrm{e}}^{-}$; C = $8{\mathrm{H}}^{+}$

3. A = $8{\mathrm{e}}^{-}$, B=${\mathrm{H}}_2$; C = $8{\mathrm{H}}^{+}$

4. A = $8{\mathrm{H}}^{+}$, B=${\mathrm{H}}_2$; C = $8{\mathrm{e}}^{-}$

The reduction of one molecule of atmospheric nitrogen (N₂) into two molecules of ammonia by nitrogenase enzyme requires

1. 4e^–, 4H⁺, and 8ATP

2. 4e^–, 4H⁺, and 16ATP

3. 8e^–, 8H⁺, and 8ATP

4. 8e^–, 8H⁺, and 16ATP

For its action, nitrogenase requires:
1.  Light
2.  Mn²⁺
3.  Super oxygen radicals
4.  High input of energy

Read the following statement & select the correct sequence of steps during symbiotic nitrogen fixation?

(a) interaction between Rhizobium & leguminous plant 

(b) Root nodule formation 

(c) Formation of ammonia

(d) leghaemoglobin

(e) Amino acid synthesis

1. a$\to$ b$\to$ c$\to$ e $\to$d

2. b$\to$ a$\to$d$\to$ e $\to$c

3. a$\to$ b$\to$c$\to$ d$\to$ e

4. a$\to$ b$\to$ d$\to$ c$\to$ e

Roots of which plant contains a pink pigment that has an affinity for oxygen:
1.  Carrot
2.  Soyabean
3.  Mustard
4.  Radish

Leghaemoglobin is produced in response to

1. respiration 

2. photosynthesis

3. fatty acid synthesis

4. N₂ fixation.