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
The synthesis of glucose from pyruvate by gluconeogenesis: 
Select and explain. 
A. Occurs exclusively in the cytosol., B. Is inhibited by an elevated level of glucagon, C. Requires the paicipation of biotin, D. Involves lactate as an intermediate
C: Requires the paicipation of biotin
Answer: C: Requires the paicipation of biotin 
Explanation: Biotin is the cofactor of pyruvate carboxylase. The carboxylation of pyruvate occurs in the mitochondria whereas the other reactions of gluconeogenesis occur in the cytosol. Glucagon stimulates gluconeogenesis. Lactate is not an intermediate in the conversion of pyruvate to glucose. Ref: Bender D.A. (2011). Chapter 44. Micronutrients: Vitamins & Minerals. 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.