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Investigating The Activity Of The Enzyme Lipase On Milk

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Introduction

Investigating The Activity Of The Enzyme Lipase On Milk Plan An Enzyme is any one of many specialized organic substances, composed of polymers of amino acids, that act as catalysts to regulate the speed of the many chemical reactions involved in the metabolism of living organisms. 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. Oxidizing enzymes, known as oxidizes, accelerate oxidation reactions; reducing enzymes speed up reduction reactions, in which oxygen is removed. Many other enzymes catalyze other types of reactions. Individual enzymes are named by adding ASE to the name of the substrate they react with. The enzyme that controls urea decomposition is called urease; those that control protein hydrolyses are known as proteinases. Some enzymes, such as the proteinases trypsin and pepsin, retain the names used before this nomenclature was adopted. Enzymes are large proteins that speed up chemical reactions. In their globular structure, one or more polypeptide chains twist and fold, bringing together a small number of amino acids to form the active site, or the location on the enzyme where the substrate binds and the reaction takes place. A catabolic enzyme splits up the substrate molecule. This process is shown below: An anabolic enzyme combines two substrate molecules. This process is shown below: Enzyme and substrate fail to bind if their shapes do not match exactly. This ensures that the enzyme does not participate in the wrong reaction. They are constructed of proteins composed of long chains of amino acids folded into a specific 3D shape held together by weak hydrogen bonds. On the enzyme there is a place called the active site and due to the way in which the protein chain is folded has a specific shape into which the substrate molecule is able to fit. ...read more.

Middle

due to their extra energy obtained by the increase in temperature. My prediction is supported by Kinetic Theory in that if I apply twice as much heat there will be twice as much particle vibration therefore the reaction will happen twice as quickly. It is also backed by Collision Theory in that if I apply twice as much heat there will be twice as many collisions and therefore the rate of reaction will double. This will only be so until the enzyme denatures after its optimum temperature: 37�C. Hypothesis I predict that the closer the temperature of the liquids to human body temperature (37�C), the faster the reaction will take place because the lipid substrate would be accustomed to working at body temperature. This would result in a faster rate of a chemical reaction and so the substrate keys would connect significantly more rapidly with their enzyme locks than if they were at a much lower or excessively high temperature. My prediction is supported by Kinetic Theory in that if I apply twice as much heat there will be twice as much particle vibration therefore the reaction will happen twice as quickly. It is also backed by Collision Theory in that if I apply twice as much heat there will be twice as many collisions and therefore the rate of reaction will double. This will only be so until the enzyme denatures after its optimum temperature. Chosen Variable * 10�C * 20�C * 30�C * 37�C * 40�C * 50�C * 60�C Fair Test I will keep this experiment a fair test by: * Using fresh pipettes for each substance to avoid contamination * Altering only the stated variable * Keeping all other variables the same * Using the same stop clock for each experiment * Having the same person timing and deciding when it is the correct time to stop the clock so the judgments will not alter * Stirring the liquids continuously and equally * Including the same quantity of phenolphthalein (1cm?) ...read more.

Conclusion

This meant I had to use a large amount of human judgment, which is not always entirely reliable in scientific conditions. If I repeated the experiment I would also take more readings for example at every 5�C and 70�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. If I had measured 70�C, I might have discovered the temperature where most of the enzymes denatured so that they had even less force to continue reacting. I found it difficult to draw my line of bestfit on both graphs because of the large jumps in rate and time of reaction. The fact that the optimum results were significantly lower on the temperature/time graph and significantly higher on the temperature/rate of reaction graph meat I had to try to accommodate them as well as the more regular readings leading up to and after the optimum temperature. The evidence that I obtained is sufficient enough to support the conclusions I have come to about the values for the optimum and denaturing temperatures because I conducted my experiment as accurately as I could with the method I used and did quite a large range and number of repetitions to the results reliable. If I was to conduct a further experiment, I would measure the relationship of relationship of temperature against time again, but I would use these values: * 31�C * 33�C * 35�C * 37�C * 39�C * 41�C This is because I would like to investigate closer if the enzymes begin to denature immediately after they have reached the optimum temperature and if they in fact reach a similar rate before hand. If I did this, I would be able to find out if 37�C really is the optimum temperature for enzymes and if 40�C is really a potentially dangerous body temperature. ...read more.

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