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
Alcohol is metabolized by ? 
Select and explain. 
A. Alcohol dehydrogenase, B. MEOS, C. Catalase, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ethyl alcohol (ethanol) is readily absorbed from GIT and degraded by oxidation (oxidative process).Liver is the major site for ethanol oxidation.At least three enzyme systems are capable of ethanol oxidation :-i) Alcohol dehydrogenase (ADH) - Major pathwayii) Microsomal ethanol oxidising system (MEOS) : It involves cytochrome P450.iii) Catalase of peroxisomes.The product of all three oxidation pathways is acetaldehyde, which is rapidly oxidized to acetate by aldehyde dehydrogenase (ALDH).