proteins

• The shape and function of a protein comes from its specific sequence of amino acids
• some functions of proteins are : enzymes, hormones, antibodies ,receptors
• a catalyst will speed up a chemical reaction, remain unchanged after the reaction, lowers energy needed for the reaction to occur
• A biological catalyst is called an ENZYME.
• During a chemical reaction the reactant that an enzyme will work on is known as the SUBSTRATE.
• The substance formed is known as the PRODUCT.
• substrate --- enzyme ---> product
• The substrate molecule fits into a special site on the enzyme called the ACTIVE SITE
• The active site and the substrate are described as being complementary in shape
• An enzyme will catalyse only one specific reaction. Just like a key will only work on a specific lock.
• Enzymes are specific and complementary in shape to the substrate.
• A degradation reaction is the breakdown of a large molecule into a small molecule(s).
• starch ---amylase---> maltose
• hydrogen peroxide ---catalase ---> oxygen+ water
• A synthesis reaction is when small molecules are built up to form a larger molecule.
• glucose-6-phosphate ---phosphorylase---> starch
• An enzyme is most active given certain conditions. These conditions are known as the optimum conditions.
• Enzymes and other proteins are affected by temperature and pH.
• In certain conditions an enzyme can become denatured. This is where the shape of the active site changes and will no longer allow the substrate to bind to it. This lowers the rate of reaction.