Enzymes and Their Importance in Plants and Animals

Enzymes are biological molecules responsible for thousands of chemical interconversions that sustain life. They (enzymes) are highly selective catalysts, greatly accelerating both the rate and specificity of metabolic reactions, from the digestion of food to the synthesis of DNA. Most enzymes are proteins, although some catalytic RNA molecules have been identified. Protein enzymes adopt a specific three dimensional structure; this is because they are made up of amino acids specifically joined together by condensation polymerisation to form peptide bonds. Like any other catalyst, enzymes speed up chemical reactions by lowering the activation energy of a reaction hence offering an alternative route for the reaction to occur. Activation energy is the minimum energy required for a reaction to start.
Enzyme’s specific tertiary structure is complementary to a specific substrate (molecules which enzymes work on to form the final product) and can only function efficiently at an optimum temperature and pH. Increasing temperature also increases the vibrational energy that molecules have, specifically in this case enzyme molecules, which puts strain on the bonds that hold them together. As temperature increases, more bonds, especially the weaker hydrogen and Ionic bonds, will break as a result of this strain. Breaking bonds within the enzyme will cause the active site to change shape. This change in shape means that the active site is less complementary to the shape of the substrate, so that it is less likely to catalyse the reaction. Eventually, the enzyme will become denatured and will no longer function. As temperature increases, more enzymes molecules' active sites' shapes will be less complementary to the shape of their substrate, and more enzymes will be denatured. This will decrease the rate of reaction. Different enzymes have different pH values at which the bonds