## ELECTRON TRANSPORT CHAIN OVERVIEW OF THE ELECTRON TRANSPORT CHAIN THE MITOCHONDRIAL ELECTRON-TRANSPORT CHAIN

### ELECTRON TRANSPORT CHAIN OVERVIEW OF THE ELECTRON TRANSPORT CHAIN THE MITOCHONDRIAL ELECTRON-TRANSPORT CHAIN

15.3.6.   The mitochondrial electron-transport chain-

The standard reduction potentials of its most mobile components are indicated, as are the points where sufficient free energy is harvested to synthesize ATP and the sites of action of several respiratory inhibitors. The Complexes I, III, and IV do not directly synthesize ATP but, rather, sequester the free energy necessary to do so by pumping protons outside the mitochondrion to form a proton gradient.

15.4.      Inhibitor of ETC

There are many inhibitor molecules which reveals the working of electron-transport chain. Following are some compounds –

Effect of inhibitors on electron transport. This diagram shows an idealized oxygen electrode trace of a mitochondrial suspension containing excess ADP and Pi. At the numbered points, the indicated reagents are injected into the sample chamber and the resulting changes in [O2] are recorded.

In ETS system, as we added $\fn_phv \beta$-hydroxy-butyrate, NAD+ linked oxidation commences as $\fn_phv \beta$-hydroxy butyrate is the source of ketone bodies. During starvation, its production increases.

As we add rotenone or amytal it interfere on inhibit NAD+ linked oxidation as it inhibit the transfer of electrons from iron-sulphur enters in complex 1 to ubiquinone. As cellular oxygen gets reduced so it creates ROS (relative oxygen species which can damage DNA and components of mitochondria).

In ETS system as succinate is added so it is generated in mitochondria by tricarboxylic acid cycle (TCA), succinate can exit the mitochondrial matrix only functional in cytoplasm as well as extra cellular space changing gene expression.

As succinate added, FAD linked glycosylation begins but antimycin is added it inhibits FAD-linked oxidation.

Cyanide is an inhibitor of enzyme cytochrome oxidase in the IV complex of ETS; as it prevent O2 from binding. As of now, O2 cannot bind nor can reduced to water. Because of this, mitochondria can't make ATP.