ETS

Definition

The Electron Transport System (ETS) is a series of protein complexes and other molecules that transfer electrons through a membrane to create a proton gradient. This process ultimately generates ATP through chemiosmosis.

5 Must Know Facts For Your Next Test

1. The ETS is located in the thylakoid membrane of chloroplasts during photosynthesis.
2. It consists of multiple complexes, including Photosystem II, cytochrome b6f complex, and Photosystem I.
3. Electrons are provided by water molecules, which are split into oxygen, protons, and electrons in Photosystem II.
4. The energy from electron transfers is used to pump protons across the thylakoid membrane, creating a proton gradient.
5. ATP synthase uses this proton gradient to produce ATP from ADP and inorganic phosphate.

Review Questions

• Where in the chloroplast does the Electron Transport System occur?
• What role does water play in the Electron Transport System during photosynthesis?
• How does the Electron Transport System contribute to ATP synthesis?

Related terms

Photosystem II:

A protein complex in the thylakoid membrane that initiates the light-dependent reactions by splitting water and releasing oxygen.

Cytochrome b6f Complex:

A protein complex that transfers electrons from Photosystem II to Photosystem I while pumping protons into the thylakoid lumen.

ATP Synthase:

An enzyme that synthesizes ATP using energy derived from a proton gradient created by the Electron Transport System.