How does temperature affect enzyme activity?

Enzymes are biological catalysts which speed up the rate of reactions. They are specific to their substrate (seen in the lock and key model) and form enzyme-substrate complexes. At low temperatures the enzyme activity will be slow, however, as the temperature increases the enzymes gain kinetic energy (they move around more). This increases the amount of successful collisions with the substrate molecules, meaning that more enzyme-substrate complexes are made. Here the enzyme is able to break down the substrate. Additionally, the high temperature will provide the enzyme with more energy to overcome the activation energy, allowing the enzyme bind with the substrate and form the enzyme-substrate complexes. The rate of reaction will continue to increase with the increase in temperature until the optimum temperature is met. After this any increase in temperature will result in a sharp decrease in enzyme activity. This is because the high temperatures denature the bonds in the enzymes tertiary structure, changing the shape of the enzymes active site so that the substrate is no longer complimentary. No more enzyme-substrate complexes can form.