Question

In Nostoc, the enzyme nitrogenase occurs in

• A. Vegetative cells
• B. Heterocysts
• C. Only in hormogones
  
• D. Both A and B
  

Answer 1

The correct option is B Heterocysts

Nostoc is a cyanobacteria. It has ability to fix atmospheric nitrogen. It converts nitrogen into ammonia. The heterocysts present in it are specialized cyanobacterial cells for nitrogen fixation. It contains enzyme nitrogenase. Nitrogenase is inactivated by oxygen. Hence, the heterocyst creates a micro anaerobic environment.

Thus, the correct answer is 'Heterocysts.'