Enzyme-Substrate Binding in a Reaction Mixture

Steps:

• Identify molecule P as the enzyme based on its role in facilitating reactions with other molecules.
• Observe that mixing leads to R and S attaching to P's active site, forming a complex.
• Rule out inhibition or product formation by checking for no blocking or breakdown evidence.
• Confirm C matches the diagram's depiction of direct active site binding.

Why C is correct:

• Enzymes bind substrates at the active site to form an enzyme-substrate complex, initiating catalysis as per the Michaelis-Menten model.

Why the others are wrong:

• A: Binding to the active site decreases, not increases, activation energy by stabilizing the transition state.
• B: Non-competitive inhibitors bind outside the active site, not forming a typical enzyme-substrate complex.
• D: Products result from reaction completion, not initial binding without evidence of P's breakdown.

Final answer: C