Question

Illustrate the mechanism of the electron transport system.

Answer 1

In the electron transport chain or system, electrons are passed from one molecule to a different one, and energy released in these electron transfers is employed to create an electrochemical gradient.

Complete answer:
The steps are involved in electron transfer chains-
-Transfer of electrons from NADH to Ubiquinone (UQ)
NADH which is produced within the mitochondrial matrix is transferred into the intermembrane space.
The NADH produced is then transferred to the electrons to FMN present within the intermembrane space via the complex I (NADH dehydrogenase).
FMN then passes the electrons to the Fe-S center (one electron to at least one Fe-S center) which then transfers the electrons, one at a time to CoQ forming semiquinone then ubiquinol.
The electron transfer creates energy that is employed to pump two protons across the membrane creating a possible gradient.
The protons withdraw to the matrix through the pore within the ATP synthase complex, forming energy within the sort of ATP.
-Transfer of electrons from ${ FADH }_{ 2 }$ to CoQ
Due to the oxidation of succinate to fumarate, the reduction of FAD to ${ FADH }_{ 2 }$ takes place.
The electrons from ${ FADH }_{ 2 }$ further enter the electron transport chain catalyzed by complex II.
Complex II does not pump a single proton across the membrane.
- Transfer of electrons from ${ CoQH }_{ 2 }$ to the cytochrome
The reduced ${ CoQH }_{ 2 }$ transfer electrons through cytochrome b and c1 which at the end reaches cytochrome.
Each cytochrome transfers one electron and thus two molecules of cytochrome are reduced for the transfer of electrons for each NADH oxidized.
The protons withdraw to the matrix through the pore within the ATP synthase complex, forming energy within the sort of ATP like within the initiative.
-Transfer of electrons from cytochrome to molecular oxygen
The final step within the electron transfer chain is catalyzed by complex IV (cytochrome oxidase) where electrons are transferred from cytochrome c to molecular oxygen.
Since two electrons are required to reduce one molecule of oxygen to water, for every NADH oxidized half oxygen is reduced to water. The transfer of protons back to the matrix leads to the formation of ATP

Note: It is asked many times where the electron transport chain takes place. The electron transport chain and site of oxidative phosphorylation are found on the inner mitochondrial membrane.