Rhizobia

Definition

Rhizobia are a group of soil bacteria that form symbiotic relationships with leguminous plants. They fix atmospheric nitrogen into a form usable by the plant, aiding in protein synthesis.

5 Must Know Facts For Your Next Test

1. Rhizobia convert atmospheric nitrogen (N2) into ammonia (NH3) through nitrogen fixation.
2. They form root nodules on legumes where nitrogen fixation occurs.
3. The enzyme nitrogenase is essential for the nitrogen-fixing process and is found in rhizobia.
4. Rhizobia benefit from carbohydrates produced by the host plant through photosynthesis.
5. This symbiotic relationship significantly enhances soil fertility and reduces the need for chemical fertilizers.

Review Questions

• What role do rhizobia play in nitrogen fixation?
• Where do rhizobia typically form symbiotic relationships?
• Which enzyme is crucial for the nitrogen-fixing process in rhizobia?

Related terms

Nitrogen Fixation:

The process of converting atmospheric nitrogen into ammonia, making it available for biological processes.

Legumes: A group of plants that have symbiotic relationships with rhizobia to fix nitrogen.

Nitrogenase: An enzyme complex responsible for the reduction of atmospheric nitrogen to ammonia in biological systems.