Question

which statement about enzymes is true?
an enzyme functions to decrease the rate of a chemical reaction.
enzymes are proteins that function as catalysts in nonliving things.
each enzyme can catalyze many different biochemical reactions.
enzymes and substrates fit together like a lock and key.

Explanation:

• Analyze each option:
• Option 1: Enzymes increase (not decrease) reaction rates, so this is false.
• Option 2: Enzymes are biological catalysts (for living organisms), not for nonliving things, so false.
• Option 3: Enzymes are specific; one enzyme typically catalyzes one (or a few related) reactions, not many different ones, so false.
• Option 4: The lock - and - key model states that enzymes and their specific substrates fit together like a lock and key, which is a correct description of enzyme - substrate interaction.

Answer:

Enzymes and substrates fit together like a lock and key.