Enzyme action

• Enzymes speed up chemical reactions by acting as a biological catalyst
• Enzymes catalyse metabolic reactions - both at a cellular level and for the organism as a whole
• Enzymes can affect structures in an organism as well as functions (like respiration)
• Enzyme action can be intracellular (Within cells) or extracellular - outside cells
• Enzymes are proteins
• Enzymes have an active site which has a specific shape. The active site is the part of the enzyme where the substrate molecules bind to
• Enzymes are highly specific due to their tertiary structure
• Enzymes lower the activation energy of a reaction
• In a chemical reaction, a certain amount of energy needs to be supplied to the chemicals before the reaction will start. This is called the activation energy - it is often provided as heat. Enzymes lower the amount of activation energy that's needed, often making reactions happen at a lower temperature than they could without an enzyme. This speeds up the rate of reaction.
• When a substrate fits into the enzymes active site it forms an enzyme-substrate complex - it's this that lowers the activation energy