Question

What are heterocysts? Where are they found?

Answer 1

Heterocysts:

1. A Heterocyst is a transparent thick-walled empty cell seen in blue-green algae filaments at an intermittent position.
2. Heterocysts are nitrogen-fixing cells generated by certain filamentous cyanobacteria, such as Nostoc punctiforme, Cylindrospermum stagnale, and Anabaena sphaerica, under nitrogen shortage.
3. They use the enzyme nitrogenase to fix nitrogen from dinitrogen (N₂) in the air in order to deliver nitrogen for biosynthesis to the cells in the filament.