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
[{'content': 'During gluconeogenesis reducing equivalents from mitochondria to cytosol are transported by - \nSelect and explain. \nA. Malate, B. Aspartate, C. Glutamate, D. Oxaloacetate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ↵\n\nGluconeogenesis is a reversal of the glycolytic pathway except for 4 thermodynamic barriers.\nThese 4 energy barriers are:-\n\n\nBetween pyruvate and phosphoenolpyruvate\nBetween fructose 1, 6-bisphosphate and fructose 6-phosphate\nBetween glucose 6-phosphate and glucose\nBetween glucose 1-phosphate and glycogen\n\n\nReducing equivalents (NADH+H+) are transported from mitochondria to cytosol in overcoming the 1" barrier i.e. \xadbetween pyruvate and phosphoenolpyruvate.\nConversion of pyruvate to phosphoenolpyruvate is achieved by 2 enzymes:-\n\n\nPyruvate carboxylase, a mitochondrial enzyme converts pyruvate to oxaloacetate (OAA).\nPhosphoenolpyruvate carboxykinase, present chiefly in the cytosol, converts OAA to phosphoenolpyruvate.\n\n\nIt is noted here that OAA is formed inside the mitochondria but the reaction to convert it into phosphoenolpyruvate occurs in cytosol and OAA is not permeable to the mitochondrial membrane.\nThe OAA is transferred to the cytosol by 2 mechanisms:-\n\n\nBy formation of Malate\nBy formation of Citrate\n\n\nThe conversion of OAA to Malate and further of Malate to phosphoenolpyruvate is depicted below. The reducing equivalents (NADH+.1-1+) are transferred across the mitochondrial membrane, along with transport of OAA in the form of malate.', 'role': 'assistant'}]