- Enzymes are biological catalysts, which speed up the rate of metabolic reactions.
- Metabolic reactions are split into two categories – anabolic and catabolic.
- Anabolic reactions build up large molecules, e.g. glycogen from glucose.
- Catabolic reactions break down large molecules, e.g. glucose from glycogen.
- Enzymes work by attaching to a substrate at its active site. The substrate then splits into a smaller molecule. They remain unchanged at the end of a reaction.