Correct option is A
Step 1: Hydrolysis of triacylglycerol by lipase (C)
- Triacylglycerol, which is a type of fat molecule, is first hydrolyzed by lipase. This step breaks triacylglycerol into glycerol and fatty acids.
- This is the initial step in lipid metabolism, as the fatty acids are now free and can be further metabolized.
Step 2: Activation of fatty acid by conjugating to CoA (D)
- The fatty acid released by the hydrolysis must now be activated to undergo further metabolism, such as beta-oxidation.
- This activation is achieved by conjugating the fatty acid to CoA (coenzyme A), forming fatty acyl-CoA. This step is crucial for enabling the fatty acid to be metabolized in the mitochondria.
Step 3: Reaction of fatty acyl-CoA with carnitine (A)
- The fatty acyl-CoA formed in the previous step cannot easily cross the mitochondrial membrane. To facilitate its entry into the mitochondria, it reacts with carnitine to form acylcarnitine.
- This reaction with carnitine allows the fatty acid to be transported into the mitochondria, where beta-oxidation occurs.
Step 4: Hydration (E)
- Once the fatty acyl-CoA (as acylcarnitine) enters the mitochondria, it undergoes the hydration step in the beta-oxidation pathway. In this step, a water molecule is added to the acyl-CoA molecule, resulting in a hydroxyacyl-CoA intermediate.
Step 5: Thiolysis (B)
- Finally, the hydroxyacyl-CoA undergoes thiolysis. During thiolysis, the bond between the carbon atoms is broken, releasing acetyl-CoA (a two-carbon fragment) and a shortened fatty acyl-CoA.
- The acetyl-CoA produced enters the Krebs cycle for further energy production, and the shortened fatty acyl-CoA continues to undergo beta-oxidation in subsequent cycles.
Correct Sequence:
- The correct sequence of these steps is:
- C → D → A → E → B
