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
Carnitine shuttle is involved in ? 
Select and explain. 
A. Fatty acid synthesis, B. Fatty acid oxidation, C. Cholesterol synthesis, D. Bile acid synthesis
B: Fatty acid oxidation
Answer: B: Fatty acid oxidation 
Explanation: Ans. is 'b' i.e., Fatty acid oxidationVery sho chain, sho chain, medium chain and long chain fatty acids get oxidized in mitochondria,Very sho chain, sho chain and medium chain fatty acids can cross inner mitochondrial membrane by passive diffusion,Long chain fatty acids cannot cross the inner mitochondrial membrane. Hence they need a carrier. The carrier is carnitine.Carnitine is p hydroxy y N trimethylaminobutyric acid. It is synthesized from lysine.