Question

Are cyanobacteria nitrogen-fixing?

Answer 1

Cyanobacteria:

1. Cyanobacteria (blue-green algae) are unicellular, aquatic organisms. They possess ‘chlorophyll a’ that helps in photosynthesis.
2. Cyanobacteria such as Nostoc and Anabaena help in nitrogen fixation. They form specialized cells called ‘heterocysts’.
3. Heterocysts contain nitrogenase enzyme that converts nitrogen to ammonia.
4. Nitrogen fixation is an essential process where the atmospheric nitrogen is converted into usable nitrites, ammonia, and nitrates. This occurs through lightning, biological, or industrial processes.
5. Since plants can not directly use free atmospheric nitrogen, they are dependent on bacteria present in the soil or root nodules for deriving this nitrogen.