Question

Select the correct statement regarding heterocyst.

• A. These are present in some filamentous cyanobacteria such as Nostoc and Anabaena
• B. These cells are specialized to perform $N_2$-fixation
• C. These cells contain enzyme nitrogenase
• D. All of these

Answer 1

The correct option is D All of these

Cyanobacteria like Nostoc and Anabaena are the organism that can fix atmospheric nitrogen in specialised cells called heterocyst. These cells contain enzyme nitrogenase which are specialized to perform $N_2$-fixation. Chemosynthetic autotrophic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production.