Question

What is the role of cytochrome a, b and c in the Electron transport Chain?

Answer 1

At their most basic, they are electron transport chains: high energy electrons are handed off through a series of donors and acceptors who use the change in energy to create concentration gradients. The energy in the electrons is transferred to potential energy in these concentration gradients. The potential energy in the [gradients] is then converted to chemical energy stored in high energy bonds. Mostly in ATP.

The actual electron transfer mechanisms and the regulation of the proteins in the electron transfer chain is much subtler and more nuanced.