Enzymes

• Living things have thousands of different metabolic reactions taking place inside them all the time
• Metabolism is the sum of all reactions taking place in a cell or the body. These reactions need to be carefully controlled
• A catalyst is a chemical that speeds up the rate of a chemical reaction without being used up.
• Enzymes are biological catalysts. They speed up the rate of chemical ractions inside the body (metabollic reactions)
• Enzymes are all proteins and all proteins are made up of chains of amino acids. These chains are folded into unique shapes, which enzymes need to do their job.
• Every reaction usually invovles molecules being slip apart or joined together.
• A substrate is a molecule that is changed in a reaction.
• Every enzyme has an active site, the part where a substrate joins on to the enzyme.
• A substrate must have the complementary shape to fit the active site - this makes enzymes very specific. This is called the 'lock and key' model, because the substrate fits into the active site of the enzyme just like a key fits into a lock.