Question

The function of leghemoglobin in the root nodules of legumes is

• A. Inhibition of nitrogenase activity
• B. Nodule differentiation
• C. Oxygen removal
• D. Expression of nif gene

Answer 1

The correct option is C

Oxygen removal

The correct option is C.

Explanation of correct option:

1. Leghemoglobin is the red-colored protein present in the root nodules of leguminous plants like beans.
2. It combines with the free oxygen in the cell and helps in oxygen removal from root nodules by sending it to the mitochondria for respiration.
3. So, the main purpose of leghemoglobin is to create an oxygen-free environment for nitrogen fixation to occur.

Explanation of incorrect options:

Option A:

1. The leghemoglobin aids the nitrogen fixation by removing the oxygen and does not inhibit nitrogenase activity.

Option B:

1. The leghemoglobin has nothing to do with the differentiation of nodules.
2. The differentiation is caused by the symbiotic relationship of the plant with nitrogen-fixing bacteria.

Option D:

1. The leghemoglobin has nothing to do with the expression of nif gene.
2. The nif gene expression is controlled by NifA protein.

Final answer: The function of leghemoglobin in the root nodules of legumes is oxygen removal.