The electron transport chain or system is the sequence of electron carriers, enzymes, and cytochrome that passes electrons from one to another through the redox reaction. It is electron transport-linked phosphorylation.
It contains flavin nucleotides (FAD), nicotinamide adenine dinucleotide (NAD), coenzyme Q, and cytochromes localized in F1 particles of mitochondria. It occurs in the inner mitochondrial membrane along with cristae.
In this process five (5) complexes are involved namely, I- NADH-UQ reductase, II- Succinate-UQ reductase, III- UQH2 -cytochrome C reductase, IV- Cytochrome C oxidase, and V is connected with F0−F1 particles.
In this process, NAD and FAD are minimized.
Steps:
Redox at complex I: Four (4) protons are pumped from the matrix to intermembrane space.
Redox at complex II: Coenzyme Q collects the electrons from complex I and II, and goes to complex III.
Redox of complex III: Four (4) protons are again pumped from matrix to intermembrane space and cytochrome C transports electrons to the complex IV.
Redox of complex IV: Two (2) protons are pumped from the matrix to intermembrane space and the formation of water occurs in the matrix.
ATP synthase action: It pumps protons from intermembrane space to matrix and generates ATP. It is associated with oxidative phosphorylation.
