MCQs

Temperature affects both reaction kinetics and enzyme stability. Even small deviations from the optimum can alter experimental results.

At substrate saturation, all available active sites are occupied, so adding more substrate cannot further increase the reaction rate.

Extreme pH alters the ionization of amino acid side chains and disrupts the interactions maintaining the enzyme's tertiary structure.

Each enzyme functions best within a specific pH range because proper ionization of amino acid residues in the active site is maintained.

With excess substrate available, more enzyme molecules provide additional active sites, increasing the overall reaction rate nearly proportionally.

Initially, more substrate molecules increase enzyme-substrate complex formation. Once all active sites become occupied, the reaction reaches maximum velocity (Vmax).

Low temperature decreases molecular motion and collision frequency. The enzyme usually regains normal activity when returned to its optimum temperature.

High temperature disrupts hydrogen bonds and other weak interactions responsible for maintaining enzyme structure, causing denaturation and loss of catalytic function.

Every enzyme has an optimum temperature where catalytic activity is highest. Above this temperature, the enzyme's three-dimensional structure begins to lose stability.

As temperature rises toward the optimum, enzyme and substrate molecules move faster, increasing successful collisions and enzyme-substrate complex formation. Denaturation usually occurs only above the optimum temperature.