The Effect of Temperature on the Rate of an Enzyme Controlled Reaction

To investigate the effect of temperature on an enzyme controlled reaction

Introduction and planning

For the investigation of enzymes, I am going to conduct an experiment to see how temperature can affect the rate of reaction of enzymes by testing it with starch.

The enzyme that we are going to use is called amylase. We are going to test this enzyme with starch. By mixing amylase and starch solutions together under different temperature conditions, we can record the rate of reaction by taking a sample out and test it with iodine solution to see if there is any remaining starch present.

We have to use the enzyme amylase because enzymes will only work on a specific substrate i.e. amylase will work on starch because of its special shape of active site. This is known as the ‘enzymes specificity'.

The enzyme amylase is used for hydrolysing starch and glycogen to form glucose and maltose. This enzyme is found in human saliva for the use of breaking down starch in food, enabling the body to absorb and produce ATP energy.

Enzymes are in all living organisms, they are proteins made up of polypeptide chains (which are made up of many amino acids) with irregular components which give it a globular shape. This makes it a dense, small, compacted molecule that can move around very easily.

For the enzyme to work, it must collide with a substrate. If they collide at the right place, the substrate will then ‘fit' into the active site of the enzyme forming enzyme-substrate complex; fitting into the active site puts a strain on bonds in the substrate, so the substrate molecule breaks up more easily. In order for any reaction to occur, there must be energy to allow it to happen; this is called the activation energy. As shown below.

http://en.wikipedia.org/wiki/Enzyme_reaction_rate

This is a general graph that shows how activation energy works. The top dotted line to the time line is the activation energy needed for the reaction without enzymes; and the second...

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