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How temperature affects enzyme activity?

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How temperature affects enzyme activity? A reaction occurs when two of the right kinds of molecules collide; enzymes which are catalysts promote these collisions. In my investigation I am going to try and find out how temperature affects enzyme activity between hydrogen peroxide and catalase. Catalase H2O2 H2O+O2. Catalysts are very useful as they are unchanged after a reaction, so they can be used over and over again unless they are damaged or denatured. Enzymes join with the substrate for a short while, the enzyme and substrate split up afterwards, releasing the enzyme. The enzyme is not used up in the process, unlike the substrate, and so it can continue to react if more substrate is provided. All enzymes are proteins. Each enzyme has a specific catalytic reaction, their normal activity depends on their environment, and if the conditions change it causes a reduced activity. Enzymes are globular proteins; their molecules are round in shape. They have an area, which is called the active site. Only the substrates fit into the active site. There are several types of enzyme which contribute to different types of biochemical reactions. Enzymes speed up reactions that much that in the absence of enzymes can cause the reaction not to take place. Enzymes are classified into several broad categories, such as hydrolytic, oxidizing, and reducing, depending on the type of reaction they control. Hydrolytic enzymes accelerate reactions in which a substance is broken down into simpler compounds through reaction with water molecules. ...read more.


Method Before starting make sure safety glasses are on, hair is tied back and work area is clear, be careful when using the Hydrogen Peroxide, as it is a corrosive chemical, Hydrogen Peroxide is a bleaching agent, so wear a lab coat so it does not bleach clothes, use a tongues to retrieve the boiling tubes from the boiling water baths, be cautious when using sharp scalpels during the experiment to prevent injuries . More than 1 person is needed for this experiment 1. Invert burette full of water in a water trough, after insuring that the tap on the burette is closed. 2. Clamp the burette in place 3. Attach one end of the tubing to the capillary tube and bung and the other end into the bottom of the inverted burette being careful not to tip the burette or to allow a lot of water into it. If air enters the burette make sure the water is up to a whole number, this will make reading the results more accrete. 4. Measure and cut a 3cm piece of potato using the ruler cutting tile and scalpel, make sure that it is exactly 3cm so that the test is fair. 5. Measure 40ml� hydrogen peroxide exactly into a beaker as this would affect the concentration and this is not a variable to be tested. 6. Heat a water bath using the Bunsen burner or to save time heat the water using a kettle and add cold water to achieve the correct temperature. Heat two boiling tubes at a time as this will save time. 7. ...read more.


This is a source of error because the concentration of catalase in the potatoes may have been different so the rate of reaction could have been inconsistent. This might be why the enzyme activity at 60�C had not completely stopped. I could repeat the experiment not with three readings at each temperature but also with three different potatoes, this would make the results more accurate. The reading of the temperature may not have been accurate as we could have read thermometer wrong or it could have been a degree over or above without us noticing, so this could have affected my results There could also have been a slight variation in the length of the potato because it was very difficult to get them all exactly 3 cm even though I was using a ruler and scalpel. Next time I would use shorted pieces of potato and could weight them so that it would know that they are the same length. I would use less hydrogen peroxide as the amount I used was probably unnecessary and would have work with a smaller amount. If I was to repeat this experiment I would also take more readings, every 5�C instead of every 10�C because if I did this I would be able to plot a more accurate graph and it would be easier and more accurate to tell when the enzyme got to the optimum and denaturing temperatures. I think that I obtain a good range of results even though I could have got more. My results are good enough to support my prediction and I have met my aim to find the effect of temperature on enzymes, using a potato as a catalyst. ...read more.

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