Question

BIOCHEMISTRY

4 complexes are involved in the electron transport chain. identify the following:

Common Complex produced by Complex I and Complex II:

Complex that reduces molecular oxygen:

Complex that is coupled to ATP synthesis:

Energy for ATP synthesis is derived from:

Net reaction that occurs at Complex I

Net reaction that occurs at Compex III

Net reaction that occurs at Complex IV

NADH donates -------- electrons during oxidation

Which of the 4 complex(es) translocate protons in the inner mitochondrial membrane?

What molecule is the electron donor to complex III?

What molecule is lipid soluble electron carrier

What is the role of Cyt C

What is the mechanism of action of uncoupling agents?

Which of the following (UQ, Cytc, Complex III) are mobile electron carrier(s)?

Answer 1

Complex IV reduces oxygen;

Complex V is involved in ATP synthesis.

ATP synthesis involves the transfer of electrons from the intermembrane space, through the inner membrane, back to the matrix. The electrons move through the electron transport chain to oxygen, where they generate energy which pumps the hydrogen ions against their concentration gradient from matrix to intermembrane space, so they can flow back down again.

Net reaction at complex I- NADH + H⁺ + CoQ + 4H⁺_in→ NAD⁺ + CoQH₂ + 4H.

Net reaction at complex III -

CoQH2 + 2 cyt c [Fe (III)] ---> CoQ + 2 cyt c. [Fe (II)] + 2 H+.

Net reaction at complex IV-  It catalyzes the transfer of electrons from ferrocytochrome c to molecular oxygen, converting the latter to water.

NADH donates --two - electrons during oxidation.

Complex I, III, and IV translocate protons in the inner mitochondrial membrane.

Ubiquinone (Q) accepts the electrons from both complex I and complex II and delivers them to complex III.

Ubiquinone: A lipid-soluble substance that is a component of the electron transport chain and accepts electrons from complexes I and II.

Cytochrome c is functionally involved in the electron transport chain of mitochondria. That electron transport is part of the pathway for synthesis of ATP. The role of cytochrome c is to carry electrons from one complex of integral membrane proteins of the inner mitochondrial membrane to another.

An uncoupler or uncoupling agent is a molecule that disrupts oxidative phosphorylation in prokaryotes and mitochondria or photophosphorylation in chloroplasts and cyanobacteria by dissociating the reactions of ATP synthesis from the electron transport chain.

Coenzyme Q (CoQ) and cytochrome c (Cyt c) are mobile electron carriers in the ETC