Enzyme Hypotheses: Lock and Key vs. Induced Fit

Steps:

• Recall lock and key hypothesis: enzyme's active site is rigid, substrate fits precisely without enzyme change.
• Recall induced fit hypothesis: enzyme's active site is flexible, changes shape to bind substrate tightly.
• Assume statement 1 describes rigid fit (lock and key), statement 2 describes shape change (induced fit), statement 3 is incorrect (e.g., no enzyme change in both).
• Evaluate: only statement 2 aligns with induced fit; statement 1 fits lock and key but question asks for both hypotheses' correct aspects.

Why C is correct:

• Induced fit involves enzyme conformational change, matching statement 2 as a key feature distinguishing it from lock and key's rigidity.

Why the others are wrong:

• A includes 1 (lock and key only, not both hypotheses) and 2.
• B includes 1 (lock and key) and 3 (likely false for both).
• D selects only 3, which misrepresents enzyme action.

Not enough information on exact statements 1–3.

Final answer: C