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
Final common pathway of metabolism of carbohydrates, lipids and protein metabolism is 
Select and explain. 
A. TCA cycle, B. Glycogenesis, C. Gluconeogenesis, D. None of the above
A: TCA cycle
Answer: A: TCA cycle 
Explanation: Final Common Oxidative Pathway Citric acid cycle may be considered as the final common oxidative pathway of all foodstuffs. all the major ingredients of foodstuffs are finally oxidized through the TCA cycle. Almost all the biochemical processes use ATP for meeting energy needs--muscle contraction, active transpo, biosynthetic reactions, etc. A thermodynamically unorable reaction when coupled with hydrolysis of ATP becomes orable.Ref: DM Vasudevan, 7th edition, page no: 250