key term - Photosystem

Definition

A photosystem is a protein complex found in the thylakoid membranes of plants, algae, and cyanobacteria that plays a critical role in the light-dependent reactions of photosynthesis. It captures photons and utilizes the energy to drive electron transport chains.

5 Must Know Facts For Your Next Test

1. There are two types of photosystems: Photosystem I (PSI) and Photosystem II (PSII).
2. Photosystem II absorbs light at a wavelength of 680 nm, while Photosystem I absorbs light at 700 nm.
3. The primary function of PSII is to generate high-energy electrons by splitting water molecules.
4. PSI uses these high-energy electrons to reduce NADP+ to NADPH.
5. Both photosystems contribute to the formation of ATP through chemiosmosis.

Review Questions

Related terms

Thylakoid Membrane: The site within chloroplasts where the photosystems are located.

Electron Transport Chain: A series of protein complexes that transfer electrons from electron donors to electron acceptors via redox reactions.

Chemiosmosis:

The process by which ATP is produced as electrons move down their concentration gradient across a membrane.