Quinone

Definition

Quinone is a class of organic compounds that play a crucial role as electron carriers in cellular respiration. They are essential for the electron transport chain, especially within the mitochondria and certain bacteria.

5 Must Know Facts For Your Next Test

1. Quinones are involved in the transfer of electrons between complexes I, II, and III in the mitochondrial electron transport chain.
2. In bacteria, quinones like ubiquinone (coenzyme Q) help facilitate oxidative phosphorylation.
3. Quinones can accept electrons and protons to form hydroquinones, which then pass these to other molecules in the electron transport chain.
4. They are lipid-soluble, allowing them to diffuse freely within the inner mitochondrial membrane or bacterial cell membrane.
5. Mutations or deficiencies affecting quinone synthesis can disrupt cellular respiration and lead to metabolic disorders.

Review Questions

• What role do quinones play in the electron transport chain?
• How do quinones contribute to oxidative phosphorylation in bacteria?
• Why is lipid solubility an important characteristic of quinones?

Related terms

Ubiquinone: A type of quinone also known as coenzyme Q, integral to mitochondrial electron transport.

Cytochrome c: A protein that transfers electrons between Complex III and Complex IV in the electron transport chain.

Oxidative Phosphorylation:

The process by which ATP is formed as electrons are transferred through the electron transport chain.