Enzymes and Their Importance in Plants and Animals
Enzymes are large proteins that are responsible for catalysing thousands of metabolic processes that sustain life. Enzymes work similarly to those catalysts used in industry by lowering activation energy and therefore dramatically speeding up the rate of a reaction, however, these biological catalysts are highly selective to their substrate. Almost every chemical reaction that occurs in a cell requires enzymes in order to occur at rates required for the sustenance of life. Enzymes have an active site which has a complimentary base to a specific substrate, when these bind an enzyme-substrate complex is formed. There are two hypotheses for the formation of an enzyme-substrate complex; the lock and key hypothesis explains that only one substrate (they key) will fit into the active site (lock). The induced fit hypothesis is when the active site changes shape so that the enzyme moulds itself around the substrate. A simple example of the importance of enzymes in digestion is lactose- intolerance. Lactose is a sugar found in milk, and is digested by an enzyme found in the intestines called lactase. A lack of this enzyme can result in lactose- intolerance, whereby the undigested lactose is fermented by bacteria causing a host of intestinal complications. However, milk can be artificially treated with purified lactase. Even if a person had the best supplemented diet, it would be worthless without the use of enzymes to allow the polymers to be broken down rapidly. The digestive system is just one of the many processes in which enzymes play a key role. The proteins and carbohydrates that we consume are polymers, they are large, insoluble molecules which mean that they cannot be directly absorbed into our blood to be assimilated into new products. They need to be hydrolysed into smaller, more soluble molecules by adding water, this hydrolysis is catalysed by a number of different enzymes. Two important glands along the...
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