Enzymes speed up reactions by making them happen quicker
Catalysts
Substances that increase the rate of a chemical reaction without being consumed or altered themselves
Enzymes
Have special shapes so they can catalyse reactions
Are really picky - they usually only catalyse one specific reaction
For enzymes to work
The substrate has to fit the enzyme's active site
Enzymes need the right temperature and pH to work best
As temperature increases
The rate of the enzyme-catalysed reaction increases
If temperature gets too high
The enzyme becomes denatured and stops working
Denatured
When the shape of an enzyme's active site is changed, so the substrate can no longer fit
All enzymes have an optimum temperature and pH that they work best at
Pepsin is an enzyme that works best at pH 2 in the acidic conditions of the stomach
If the pH is too high or too low, it interferes with the bonds holding the enzyme together, changing the shape of the active site and denaturing the enzyme
