Question

Cyanobacteria are obviously capable of photosynthesis, but many of them also convert nitrogen gas into reduced forms of nitrogen (such as ammonia) that can be used by cells in the synthesis of nitrogen-containing organic compounds, including amino acids and nucleotides. This process is called ______.

a) nitrogen fixation
b) denitrification
c) nitrification
d) respiration
e) ammoniation

Answer 1

The process by which cyanobacteria convert atmospheric nitrogen into ammonia is called nitrogen fixation, which is vital for the synthesis of organic compounds in ecosystems. The correct option is a).

Step-by-step explanation:

Cyanobacteria are single-celled organisms that perform a critical role in nitrogen cycling in ecosystems through a process known as nitrogen fixation. These organisms are able to convert atmospheric nitrogen (₂N²) into a form that is usable by plants and other organisms, such as ammonia (₃NH).

Nitrogen fixation is vital for synthesizing nitrogen-containing organic compounds such as amino acids and nucleotides.

Cyanobacteria can carry out this process due to the presence of heterocysts, specialized cells which create anaerobic conditions necessary for the nitrogenase enzyme to function and convert ₂N into ₃NH. Therefore, the correct answer to the question is a) nitrogen fixation.