Plastoquinone Q H2

Plastoquinones Q H is a molecule in the electron transfer system betweeen photosystem II (PSII) and photosystem I. The sequence of carriers is as follows: Pheophytin -> Q A -> Q B -> Q H -> Cytochrome b 6f. Plastoquinone Q H2 is the photosynthetic equivalent of coenzyme Q of the electron transport system. It moves freely in the thylakoid membrane, carry electrons between the photosystem II complex and the cytochrome b 6f complex (Figure 17.12). Electron transfer involving plastoquinones is shown here. Reduction of a plastoquinone creates a plastoquinol.

See also: Plastoquinones, Photosystem II, Photosystem I, Plastoquinone Q H, Pheophytin, Plastoquinone Q B