Biology - Enzymes

What so enzymes act as in living things?

Biological catalysts

What is a catalyst?

A substance whuch increases the speed of a reaction without being changed or used up in the reaction

What are enzymes?

Large proteins that are made up of chains of amino acids folded in unique shapes

What do chemical reactions usually involve?

Things either being split apart or joined together

Why do enzymes only catalyse into one specific reaction?

Because the substrate has to fit into its active site, if the substrate doesnt match the enzymes active site, the reaction wont be catalysed

What is it called when the actuve site changes shape as the substrate binds to it to get a tighter fit?

The ‘induced fit’ model of an enzyme model

What is a substrate?

The substance that the enzyme acts on

Does a higher temperature increase or decrease enzyme catalyst reactions?

Increases

What happens to the enzyme if the temperature gets too hot?

Some of the bonds holding the enzyme together will break, which chabges the shape of the active site meaning the susbtance will no longer fit. This enzyme is called ‘denatured’

What happens to the enzyme if the ph levels are too high or low?

The pH interferes with the bonds holding the enzyme together. This also changes the active site shape and denatures the enzyme.

What is an enzymes optimum pH?

Often neutral pH 7.

Sometimes it can be different — eg. Pepsin breaks down porteins in the stomach and works best at pH 2. (Suited to the acidic conditions)