Question

Explain how the Q-cycle contributes to producing the proton gradient in the ETC?

Answer 1

The Coenzhme Q which is lipophilic and is mobile have the ability to convert into 2 forms, that is ubiquinol and ubiquinone. Ubiquinone is converted to ubiquinol after receiving electrons from either Complex 1 or complex3.

In both cases when it recieves electrons it draws 2 H+ ions from the cytoplasm to bond using the electrons recieved. When it transfers electron to complex 2 it agaian converted to ubiquinone and thus transfere H+ ions into intermembrane space.