Question

Heterocysts are specialized for nitrogen fixation as they are

• A. Impermeable to oxygen
• B. Impermeable to nitrogen
• C. Lacking water-splitting in photosystem 2
• D. Both (A) and (C)

Answer 1

The correct option is D

Both (A) and (C)

The correct option is D.

Explanation of the correct option:

1. A heterocyst is a differentiated cyanobacterial cell that performs nitrogen fixation.
2. Heterocysts serve as sites for nitrogen fixation under aerobic conditions.
3. They are formed in response to a certain nitrogen deficiency.
4. They have an additional glycolipid layer that makes them impermeable to oxygen.
5. They have degraded photosystem 2 and fail to generate oxygen.
6. They lack water splitting photosystem 2.

Explanation of the incorrect options:

Option B:

1. Heterocysts are nitrogen permeable and carry out nitrogen fixation.

Final answer: Heterocysts are specialized for nitrogen fixation as they are impermeable to oxygen and lack water splitting photosystem 2.