Enhancement of Food Production — BIOLOGY STD 12 Science — Question

Blue-green algae or cyanobacteria such as Nostoc, Anabaena possess specialized cells. These cells are called as heterocysts. These are modified cells which are formed from the vegetative cells. These are the sites for N2 fixation. There is an enzyme in the heterocyst called as nitrogenase which helps in nitrogen fixation. These cells also perform oxygenic photosynthesis.