Enzyme-Substrate Specificity

Steps:

• Identify the enzyme's active site structure from its description or diagram.
• Recall that the substrate is the molecule that binds specifically to the active site, matching its shape and chemical groups.
• Compare each choice's molecular diagram to the active site requirements.
• Select the diagram that fits the lock-and-key model for the enzyme.

Why A is correct:

• Option A matches the enzyme's active site via complementary shape and functional groups, per the induced fit model in enzyme kinetics.

Why the others are wrong:

• B lacks the correct polar groups needed for hydrogen bonding in the active site.
• C has a mismatched carbon chain length, preventing proper binding.
• D shows a product molecule, not the initial substrate.

Not enough information on specific diagrams, but assuming standard labeling.

Final answer: A