What happens to an enzyme when the temperature or pH of its environment changes?

• A. The enzyme changes its substrate specificity.
• B. The enzyme remains unchanged and continues to function normally.
• C. The enzyme becomes more efficient and speeds up reactions.
• D. The enzyme becomes denatured and loses its function.

Answer: (D)

Verified step by step guidance

1. Understand that enzymes are proteins that catalyze biochemical reactions by lowering the activation energy required for the reaction to proceed.
2. Recognize that enzymes have an optimal temperature and pH at which they function most efficiently. Deviations from these optimal conditions can affect enzyme activity.
3. When the temperature increases beyond the optimal range, the increased kinetic energy can cause the enzyme's structure to become unstable, leading to denaturation. Denaturation involves the unfolding of the enzyme's three-dimensional structure, which is crucial for its function.
4. Similarly, changes in pH can affect the ionization of amino acids at the active site or elsewhere in the enzyme, disrupting hydrogen bonds and ionic interactions that maintain the enzyme's structure, leading to denaturation.
5. Once denatured, the enzyme loses its specific shape, including the active site, and can no longer bind to its substrate effectively, resulting in a loss of enzymatic activity.