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The effect of enzyme concentration on the rate of an enzymic controlled reaction.

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Introduction

AS Level Biology Practical Skills Assessment Eloise Tarling The effect of enzyme concentration on the rate of an enzymic controlled reaction. The effect of enzyme concentration on the rate of an enzymic controlled reaction. Enzymes are protein molecules, which can be defined as Biological catalysts, which alter the rate of a reaction without the enzymes undergoing change themselves. Enzymes are usually specific to one singular reaction. Enzymes are globular proteins with the helix coiled into a precise three-dimensional tertiary structure, with Hydrophilic R groups held by four different types of bonds: 1. Hydrogen 2. Disulphide 3. Ionic 4. Hydrophilic / Hydrophobic Enzymes possess an active site, a region, usually a cleft or depression to which another molecule can bind. This specific molecule is the enzymes' substrate. The precise shape of the active site allows the substrate to bind perfectly to the active site. ...read more.

Middle

When investigating the effect of enzyme concentration it is fairest to look at initial rate of reaction, as once the reaction is underway, the amount of substrate available in the reaction begins to vary, as substrate is converted to products at different rates, all depending upon concentration. When the Enzyme-Substrate Complex is initially formed, there are a large number of substrate molecules available, meaning every enzyme molecule has a substrate molecule in its active site. This allows for the V Max rate of reaction, V Max being where the enzyme is working at its maximum possible rate. Rate of reaction depends upon the number of enzyme molecules available, and the speed at which the enzyme molecules convert substrate molecules into products. As the reaction continues, there are gradually fewer substrate molecules, meaning the speed of the reaction will decrease until the reaction eventually ceases. ...read more.

Conclusion

* The lower the enzyme concentration, the slower the rate of the reaction. During this investigation, I will be controlling the following variables: * Temperature (consistent at 40 C). * Time of recording results (every 30 seconds for 5 minutes, including a reading at 0). Prior to this investigation, I carried out the experiment that I will be using for my practical assessment to familiarise myself with the method. However, in my preliminary experiment, I focussed upon identifying the course of an enzyme-controlled reaction. For this investigation, I will be altering the concentrations of enzyme, temperatures, and times of recording results, from those used in my preliminary experiment. I will be using 5 different enzyme concentrations, opposed to the single concentration included in the preliminary experiment, and I will be concentrating upon one particular temperature, being 40 C. In order ensure the validity of my experiment; I will take three recording of each enzyme concentration at 40 C, instead of one, as in my preliminary experiment. ...read more.

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