Which complex in the electron transport chain is not directly involved in the establishment of conditions for ATP synthesis?

• A. Complex III
• B. Complex II
• C. Complex I
• D. Complex IV

Answer: (B)

Verified step by step guidance

1. Understand the role of each complex in the electron transport chain. The electron transport chain consists of four main complexes: Complex I, Complex II, Complex III, and Complex IV.
2. Complex I is involved in the transfer of electrons from NADH to ubiquinone, contributing to the proton gradient across the inner mitochondrial membrane.
3. Complex II, also known as succinate dehydrogenase, transfers electrons from succinate to ubiquinone but does not contribute to the proton gradient, which is crucial for ATP synthesis.
4. Complex III transfers electrons from ubiquinol to cytochrome c and contributes to the proton gradient by pumping protons across the membrane.
5. Complex IV transfers electrons from cytochrome c to oxygen, forming water, and also contributes to the proton gradient by pumping protons across the membrane.