Biology Foundation - Effect of Temperature on the Action of an Enzyme As a method of investigating the effect of temperature on enzyme action, what are the shortcomings of this experiment?
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Biology Foundation - Effect of Temperature on the Action of an Enzyme As a method of investigating the effect of temperature on enzyme action, what are the shortcomings of this experiment? What could be done to improve it? Suggest further experiments you might carry out to examine the effect of temperature on the inactivation of the enzyme. Enzymes have a specific three-dimensional shape. They are large molecules, usually much bigger than their substrates, but only a relatively small part of the enzyme actually comes into contact with the substrate. This area of the enzyme is called its active site. Each enzyme can catalyse only one particular reaction, because an enzyme can only react with a specific substrate molecule. In this case, Amylase can only catalyse the hydrolysis of starch into smaller disaccharide maltose molecules. This is because amylase can only react with starch molecules specifically in the way cellulase 'breaks down' cellulose specifically.
The rate of enzyme-catalysed reactions reaches a peak at a particular temperature. This is the optimum temperature for the reaction. Any increase in temperature also causes the atoms making up the enzyme molecule to vibrate more. Eventually this vibrating causes the breaking of the hydrogen bonds and other bonds that hold the enzyme molecule in its tertiary structure, with its specific shape. Its three-dimensional shape alters, including the active site, which will no longer fit the substrate molecule. The enzyme is Denatured. This is a permanent change that cannot be reversed by cooling. Addressing the issue of the shortcomings of this experiment, it could be said that at what point is denaturing irreversible? Just prior to this point, is it reversible? In order to investigate this further it could be said that the experimental reactants should be maintained at the given temperature throughout the experiment to ensure any potentially reversible denaturation is maintained throughout the course of the experiment.
This is due to changes in the enzyme Active Site and as temperature is increased, this will eventually lead to denaturing. This can be explained by taking the example of the reaction leading up to 85o C. The rate of reaction slows down due to the Carbon, Hydrogen, Oxygen and Nitrogen atoms vibrating furiously due to increased heat equals increased kinetic (movement) energy which leads to the Active Site not maintaining its integrity and consistency and after time not holding its shape. While it can still catalyse, the reaction is not efficient. When the temperature increases to 85o C the active site has been destroyed hence the reaction ceases i.e. the albumen in eggs is runny when the egg is cold however after being boiled the albumen become hard and white. This is a classic example of denaturing. Stan Howell - Biology Foundation - Amylase Practical 1
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