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': 'The first step in fatty acid synthesis involves \nSelect and explain. \nA. Acetyl CoA carboxylase, B. b-Hydroxyl CoA dehydrogenase, C. Acetyl dehydrogenase, D. Pyruvate kinase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Acetyl CoA carboxylase\xa0\n\nProduction of malonyl-CoA from acetyl-CoA is the initial and rate limiting step in fatty acid synthesis. The reaction is catalyzed by acetyl-CoA carboxylase.', 'role': 'assistant'}]