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': 'Which of the following enzyme does not catalyse reversible step in glycolysis? \nSelect and explain. \nA. PFK, B. Enolase, C. Phosphoglyceromutase, D. Glyceraldehyde-3-phosphate dehydrogenase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Enzymes of glycolysis - a process which converts 6 carbon glucose to 3 carbon unit pyruvate & lactate - are present in cytoplasm. Whereas,\xa0complete oxidation of glucose (to CO2 & H2O) requires mitochondrial enzymes (of TCA cycle).\nOut of total 9 enzymes used in glycolysis,\n3 enzymes - hexokinase, phosphofructokinase (PFK-1) and\xa0pyruvate kinase are used in\xa0 irreversible steps.\n6 enzymes - phosphohexose isomerase, aldolase,\xa0 glyceraldehyde-3-phosphate dehydrogenase, 1, 3-bisphosphoglycerate kinase, phosphoglyceromutase and enolase are used in reversible steps.\n2 enzymes used in energy utilizing steps are - hexokinase (using 1 ATP) and phosphofructokinase / PFK-1 (using\xa01 ATP). This energy consumption is for 1 molecule of glucose.\n3 enzymes used in energy producing steps are - glyceraldehyde-3-phosphate dehydrogenase (producing 2 NADH =\xa05 ATP), 1, 3-bisphosphoglycerate kinase (producing 2 ATP)\xa0and pyruvate kinase (producing 2 ATP). This energy\xa0production is for 1 molecule of glucose or 2 molecules of glyceraldehyde-3-phosphate.', 'role': 'assistant'}]