Question

1. Explain how the electron transport chain is coupled to the production of ATP via ATP Synthase.

Answer 1

Oxygen is the prime component in oxidative phosphorylation which is divided into two parts namely electron transport chain and chemiosmotic coupling. Site for electon transport chain is usually in the inner membrane of mitochondria which consists of series of complexes and protein units that transfers the electrons along finally resulting into generation of energy.

The electrons are received at the starting point of the chain thereby getting transfered through the chain from I to IV complexes by decreasing in energy, thus building a proton gradient which pumps the proton into the inner membrane of mitochondria.. This results in high amount of H+ in the intermembrane of mitochondria and low amount in the matrix area. Now as the proton is hydrophobic in nature, it cannot pass through the lipidic nature of the membrane on its own. It requires a carrier molecule which acts as a tunnel to take through it. Here comes ATP synthase into action, by turning into carrier as it is a membrane spanning protein unit. The protons use this channel to flow down the gradient. A this takes place, ADP is added with phosphate and released energy is formed as ATP which was supposed to be lost as heat energy if not properly organized. Thus ATP production is concluding part of the electron transport chain.