2.9 understand how the functioning of enzymes can be affected by changes in temperature, including changes due to change in active site

As heat increases kinetic energy increases, so particles and substrates will be more likely to collide

and bind, increasing the speed of reaction. Heat increase = amount of reactions an enzyme 

catalyses increase.

If the temperature gets too high, the enzyme will start to denature, this causes a change in the active site, the enzyme will no longer be able to bind molecules

If the temperature gets colder the enzyme gets less energy so there are less frequent collisions = less reactions