Key learning points

1. The rate of a reaction is the amount of change (e.g. substrate broken down or product made) per unit of time.
2. Enzyme reaction rate increases as substrate concentration increases, until an optimum when all active sites are full.
3. Enzyme reaction rate increases with temperature due to more collisions, until an optimum when all active sites are full.
4. Enzyme reaction rate decreases as temperature increases above the optimum, as the active site becomes denatured.
5. Interpretation of graphs showing effects of substrate concentration and temperature on enzyme reaction rate.

Keywords

• Rate of reaction - A measure of how much change occurs per unit of time.

• Concentration - A measure of the quantity of a dissolved substance in a given volume of solution.

• Optimum - The conditions where maximum rate of reaction occurs.

• Denatured - A permanent change in the shape of an enzyme which stops it from working.

Common misconception