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Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statements is not correct during this process of nitrogen fixation?
A
Leghaemoglobin scavenges oxygen and is pinkish in colour
B
Nodules act as sites for nitrogen fixation
C
The enzyme nitrogenase catalyses the conversion of atmospheric $N_2$ to $NH_3$
D
Nitrogenase is insensitive to oxygen
Detailed Solution
Root nodules of legumes, formed by $Rhizobium$, are the sites of nitrogen fixation (correct).
The nodule contains the enzyme nitrogenase, a Mo–Fe protein, which catalyses the conversion of atmospheric nitrogen to ammonia: $N_2 + 8e^- + 8H^+ + 16ATP \rightarrow 2NH_3 + H_2 + 16ADP + 16P_i$ (correct).
Nitrogenase is highly sensitive to molecular oxygen; it requires anaerobic conditions.
To protect it, the nodule contains the pink pigment leghaemoglobin, which acts as an oxygen scavenger (correct).
Hence the statement that nitrogenase is insensitive to oxygen is not correct.
The nodule contains the enzyme nitrogenase, a Mo–Fe protein, which catalyses the conversion of atmospheric nitrogen to ammonia: $N_2 + 8e^- + 8H^+ + 16ATP \rightarrow 2NH_3 + H_2 + 16ADP + 16P_i$ (correct).
Nitrogenase is highly sensitive to molecular oxygen; it requires anaerobic conditions.
To protect it, the nodule contains the pink pigment leghaemoglobin, which acts as an oxygen scavenger (correct).
Hence the statement that nitrogenase is insensitive to oxygen is not correct.