Enzyme Denaturation in Temperature Graphs

Steps:

• Enzyme reaction rates increase with temperature as kinetic energy rises, speeding collisions.
• At higher temperatures, enzymes reach an optimum where activity peaks.
• Beyond optimum, heat disrupts enzyme structure, causing denaturation and rate drop.
• Graph part X shows this decline, indicating denaturation onset.

Why C is correct:

• Enzymes are proteins that denature above optimal temperature, losing tertiary structure and active site function per protein folding principles.

Why the others are wrong:

• A: Graph plots increasing temperature effects; drop isn't reversal but structural damage.
• B: Substrates rarely denature first; enzymes are more temperature-sensitive proteins.
• D: Enzyme depletion relates to concentration, not temperature variation.

Final answer: C