Question

Cytochrome ‘C’ transfers the electrons between:

• A. Complex I and II
• B. Complex II and III
• C. Complex III and IV
• D. Complex IV and ATP synthase

Hint:

Cytochrome C is an essential electron carrier in the mitochondrial electron transport chain, connecting Complex III and Complex IV.

Answer 1

The Correct Option is C

In the electron transport chain (ETC), cytochrome C plays an important role in transferring electrons between Complex III (cytochrome bc1 complex) and Complex IV (cytochrome c oxidase). Cytochrome C is a small heme-containing protein that shuttles electrons from the reduced form of cytochrome b (in Complex III) to cytochrome a and a3 (in Complex IV), facilitating the final steps of electron transfer before the electrons are used to reduce oxygen to water. Here’s why the other options are incorrect:
- Complex I and II: Cytochrome C does not interact with Complex I and II; rather, it shuttles electrons from Complex III to Complex IV.
- Complex II and III: Complex II does not use cytochrome C for electron transfer.
- Complex IV and ATP synthase: Cytochrome C does not transfer electrons between Complex IV and ATP synthase; ATP synthase is involved in the production of ATP, not electron transfer. Thus, the correct answer is Complex III and IV.