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
Which of the following metabolic processes occurs exclusively in the mitochondria? 
Select and explain. 
A. Cholesterol synthesis, B. Fatty acid synthesis, C. Gluconeogenesis, D. Ketone body synthesis
D: Ketone body synthesis
Answer: D: Ketone body synthesis 
Explanation: Of the processes listed, only ketone body synthesis occurs exclusively in the mitochondria. Other mitochondrial processes include the production of acetyl-CoA, the TCA cycle, the electron transpo chain, and fatty acid oxidation. Processes that occur exclusively in the cytoplasm include cholesterol synthesis (in cytosol or in ER), fatty acid synthesis, glycolysis, and the hexose monophosphate shunt. Note that gluconeogenesis and the urea cycle occur in both the mitochondria and the cytoplasm. Ref: Botham K.M., Mayes P.A. (2011). Chapter 22. Oxidation of Fatty Acids: Ketogenesis. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.