This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Cytosolic Cytochrome C mediates 
Select and explain. 
A. Apoptosis, B. Electron transpo, C. Krebs cycle, D. Glycolysis
A: Apoptosis
Answer: A: Apoptosis 
Explanation: A i.e. Apoptosis Cytochrome C has two very opposite roles. Within the mitochondrial membrane it serves as electron carrier in oxidative phosphorylation. But when it leaks out into cytosol it combines with Apaf I and activates caspase-9 to mediate apoptosisQ. This dual functioning is known as moonlighting.