This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
Number of ATP formed per turn of citric acid cycle is 
Select and explain. 
A. 5, B. 7, C. 10, D. 15
C: 10
Answer: C: 10 
Explanation: TEN ATP ARE FORMED PER TURN OF THE CITRIC ACID CYCLE As a result of oxidations catalyzed by the dehydrogenases of the citric acid cycle, three molecules of NADH and one of FADH2 are produced for each molecule of acetyl-CoA catabolized in one turn of the cycle. These reducing equivalents are transferred to the respiratory chain, where reoxidation of each NADH results in the formation of ~2.5 ATP, and of FADH2, ~1.5 ATP. In addition, 1 ATP (or GTP) is formed by substrate-level phosphorylation catalyzed by succinate thiokinase. Reference: Harper; 30th edition; Page no: 164