Granum

Definition

A granum is a stack of thylakoid membranes found within the chloroplasts of plant cells. It plays a critical role in the light-dependent reactions of photosynthesis, where light energy is converted into chemical energy.

5 Must Know Facts For Your Next Test

1. Grana (plural for granum) are connected by intergranal or stromal thylakoids.
2. The thylakoid membranes within a granum contain chlorophyll and other pigments essential for capturing light energy.
3. Clusters of grana increase the surface area for light absorption, enhancing photosynthetic efficiency.
4. Photosystem II is primarily located in the grana, playing a pivotal role in water splitting and oxygen release.
5. ATP and NADPH produced during the light-dependent reactions occur in the thylakoid membranes of grana.

Review Questions

• What is the primary function of a granum in photosynthesis?
• How do grana contribute to increasing photosynthetic efficiency?
• What photosystem is predominantly found in the grana?

Related terms

Thylakoid: Membrane-bound compartments inside chloroplasts where light-dependent reactions of photosynthesis take place.

Chlorophyll: A green pigment located within thylakoid membranes that captures light energy for photosynthesis.

Photosystem II: A protein complex located in the thylakoid membrane that plays a crucial role in water splitting and oxygen evolution during photosynthesis.