heterocyst
/ˈhɛtərəˌsɪst/
noun
- A specialized, thick-walled cell found in certain types of cyanobacteria (blue-green algae) that is responsible for fixing nitrogen from the air.
- The cyanobacterium forms a heterocyst when there is not enough nitrogen in the water.
- Scientists study the heterocyst to understand how bacteria convert nitrogen into a form that plants can use.
- Under a microscope, the heterocyst appears as a larger, clear cell among the chains of bacteria.