CHEMIOSMOSIS

Electron Transport Chain

An electron transport chain is a series of compounds that transfer electrons from electron donors to electron acceptors via redox reactions, and couples this electron transfer with the transfer of protons (in the form of H+) across a membrane. This creates an electrochemical proton gradient that drives the synthesis of adenosine triphosphate, a molecule that stores energy chemically in the form of highly strained bonds. The molecules of the chain include peptides, enzymes, and others. The final acceptor of electrons in the electron transport chain during aerobic respiration is molecular oxygen although a variety of acceptors other than oxygen such as sulfate exist in anaerobic respiration.

Where does the energy released, from the process of electron carriers oxidizing NADH + H+ AND FADH2, go?

It is used to move protons against their concentration gradient, from the mitochondrial matrix into the space between the two membranes.

Summary

Occurring in the membrane, H+ are transported across the membrane into/out of the matrix. Chemiosmosis involves the establishment of a proton gradient across a membrane- used to drive ATP Synthesis. Energy from the electrons is used to transport H+.

Chemiosmosis

The process in which electron transport is coupled to ATP synthesis.

ATP synthase

This enzyme uses the proton gradient to catalyse ATP synthesis.