5.21—Temperature, enzyme activity and Q10

Raising temperature usually increases enzyme rate because molecules move faster and collide successfully more often, up to an optimum. Above that point, bonds maintaining tertiary structure break, the active site changes and the rate falls.

Different organisms and enzymes have different optima. Temperature therefore affects metabolism, photosynthesis, development and species distributions through specific enzyme-controlled processes rather than a single universal threshold.

Warmer water may speed cyanobacterial photosynthesis and bloom growth, while excessive heat can increase photorespiration or reduce hatch rates when developmental enzymes or proteins are damaged.

An optimum is not always 35 °C, and slower activity at low temperature is not denaturation. Identify whether the change is reversible slowing or permanent loss of active-site shape.