biological molecules

When the temperature is raised the kinetic energy of the molecules increases and they begin vibrate. When the kinetic energy possessed by the molecules becomes very large the vibrations become too large and the bonds between the molecules break. This changes the active site of the enzymes and so the substrate can no longer bind and form an enzyme substrate complex. We can now say that the enzyme is denatured.

Enzymes work best at an optimum pH.Outside this pH the enzyme will lose its tertiary structure and become denatured.Thus it will no longer act as a catalyst.

Water has a high specific heat capacity therefore a small change of temperature in water requires a large heat transfer.This , therefore minimizes the change in the cells of organisms.