Which of the following statements correctly describes the role of quinones in the electron transport chain?

• A. Quinones are lipid-soluble molecules that can carry 2 electrons and diffuse through the membrane.
• B. Quinones are water-soluble molecules that can carry 2 electrons and are located in the cytoplasm.
• C. Quinones are protein-bound molecules that can carry 1 electron and are fixed within the membrane.
• D. Quinones are lipid-soluble molecules that can carry 1 electron and are located in the intermembrane space.

Answer: (A)