What is the primary function of heterocysts in cyanobacteria?

The primary function of heterocysts in cyanobacteria is nitrogen fixation. These specialized cells provide an anaerobic environment that is crucial for the enzyme nitrogenase to function effectively, as nitrogenase is sensitive to oxygen. Heterocysts facilitate the conversion of atmospheric nitrogen (N2) into ammonia (NH3), which can then be used by the organism to synthesize essential compounds like amino acids and nucleotides. This process is vital for the growth of cyanobacteria, especially in environments where nitrogen is a limiting nutrient. The presence of heterocysts allows cyanobacteria to thrive in a variety of ecosystems, contributing significantly to the nitrogen cycle by enriching the soil and supporting plant growth in surrounding areas.