This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fat and Carbohydrate interconversion, Subject name: Biochemistry
Acetyl CoA cannot be conveed to: 
Select and explain. 
A. Fatty Acids, B. Glucose, C. Ketone Bodies, D. Cholesterol
B: Glucose
Answer: B: Glucose 
Explanation: Acetyl CoA is a staing material for Fatty Acid Synthesis, Cholesterol Synthesis & Ketone Body Synthesis (option a, c & d). But Acetyl CoA is never a substrate for Gluconeogenesis i.e. it can never form glucose (option b). Because Acetyl CoA can never be conveed back to Pyruvate as Link reaction or Pyruvate Dehydrogenase is irreversible. However, acetyl-CoA can stimulate gluconeogenesis by activating pyruvate carboxylase (see fig) Extra Edge: Acetyl CoA is NOT:- Not The intermediate of TCA. The first substrate of TCA. The carrier of TCA .