Question

How many feature/s are related to heterocyst ?
1) Has no cell wall
2) Contains nitrogenase enzyme
3) Promotes fragmentation
4) Can be seen in Nostoc
5) Possesses PS II

• A. 5
• B. 3
• C. 2
• D. 4

Answer 1

Answer: (B)

3

Heterocyst is a specialized nitrogen=fixing cell found in some filamentous cyanobacteria like Nostoc, Anabaena. It has cell wall which is made up of three layers. It carries carries out nitrogen fixation. It is formed due to lack of fixed nitrogen. It fixes nitrogen under aerobic conditions. It contains nif gens and synthesize nitrogenase enzyme. Apart from nitrogenase enzymes, it also contains other enzymes required for nitrogen fixation. It promotes vegetative reproduction by filament fragmentation. It does not possesses PS II and hence cannot produce oxygen.

Thus, the correct answer is option B.