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 first step in fatty acid synthesis involves 
Select and explain. 
A. Acetyl CoA carboxylase, B. b-Hydroxyl CoA dehydrogenase, C. Acetyl dehydrogenase, D. Pyruvate kinase
A: Acetyl CoA carboxylase
Answer: A: Acetyl CoA carboxylase 
Explanation: Acetyl CoA carboxylase 

Production 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.