The Importance of Enzymes in Plants and Animals Essay

1105 Words Feb 15th, 2013 5 Pages
Enzymes and their importance in plants and animals (25 marks)
Enzymes are biological catalysts, which accelerate the speed of chemical reactions in the body without being used up or changed in the process. Animals and plants contain enzymes which help break down fats, carbohydrates and proteins into smaller molecules the cells can use to get energy and carry out the processes that allow the plant or animal to survive. Without enzymes, most physiological processes would not take place. Hundreds of different types of enzymes are present in plant and animal cells and each is very specific in its function. Enzymes have an active site which has a complimentary base to a specific substrate, when these bind an enzyme-substrate complex is
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However if the temperature exceeds the optimum temperature the enzyme becomes denatured. This is because there is too much energy causing the enzyme molecules to vibrate causing the bonds maintaining their tertiary structure to break. The enzyme unravels causing the shape of the active site to change so it can no longer fit with the substrate. Changes in pH also alter an enzyme’s shape. Different enzymes work best at different pH values. The optimum pH for an enzyme depends on where it normally works. For example, intestinal enzymes have an optimum pH of about 7.5 whereas enzymes in the stomach have an optimum pH of about 2. Substrate concentration also affects the rate of reaction as the greater the substrate concentration the faster the rate of reaction and all the active sites are filled. At this point the rate of reaction can only be increased if you add more enzymes in to make more active sites available. An inhibitor is a substance that slows down or stops enzyme-substrate complexes forming. Competitive inhibitors have a similar shape to the substrate which allows them to enter the active site so the substrate cannot; therefore they both compete for the active site. If you add more substrate the effect of the competitive inhibitor will be reduced. Non-competitive inhibitors bind to the enzyme away from the active site but change the tertiary stricture of the protein and so the shape of the active sit. This means that the
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