Question

How many of the four membrane bound complexes identified in mitochondria are the proton pumps?

• A. 1
• B. 3
• C. 2
• D. 4

Answer 1

The correct option is B 3

Mitochondrial redox carriers include 4 complexes. Complex I is NADH-coenzyme Q reductase. Complex II is succinate dehydrogenase. Complex III is cytochrome $b{c}_1$ complex. Complex IV is cytochrome c oxidase. Four membrane-bound complexes have been identified in mitochondria. Each is an extremely complex transmembrane structure that is embedded in the inner membrane. Three of them are proton pumps. They are complex 1, 3 and 4. Complex 2 does not move the protons across the mitochondrial membrane.

So, the correct answer is '3'