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
In oxidative phosphorylation, the ATP production and respiratory chain are linked by 
Select and explain. 
A. Chemical methods, B. Physical methods, C. Chemiosmotic methods, D. Conformational changes
C: Chemiosmotic methods
Answer: C: Chemiosmotic methods 
Explanation: The chemiosmotic coupling hypothesis is the most accepted theory which explains the mechanism of oxidative phosphorylation.
The theory states that free energy of electron transport is conserved by pumping protons (111 from mitochondrial matrix to the intermembrane space, so as to create an electrochemical proton gradient across the inner mitochondrial membrane. The electrochemical potential of this gradient is used to synthesize ATP.