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To investigate the factors that affect the time taken for the digestion of casein in milk by trypsin, and to see what factors will make the reaction go faster or slower.

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AIM: To investigate the factors that affect the time taken for the digestion of casein in milk by trypsin, and to see what factors will make the reaction go faster or slower. BACKGROUND INFORMATION: Enzymes are proteins that act as biological catalysts and are found in cells. They speed up the chemical reactions in living things. Our guts would take weeks and weeks to digest our food without enzymes, our muscles, nerves and bones would not work properly and so on - we would not be living without them. TABLE OF DIGESTIVE ENZYMES: SECRETIONS ACTION Salivary Glands Amylase Starch --> Maltose Stomach Pepsin Proteins --> Polypeptides HCR Kills bacteria Pancreas Amylase Starch --> Maltose Trypsin Polypeptides --> Amino acids Lipase Fats --> Fatty acids + Glycerol Liver Bile Emulsifies fats Ileum Maltase Maltose --> Glucose Sucrase Sucrose --> Glucose + Fructose A catalyst is any chemical substance that makes a chemical reaction go faster, without being changed itself. A catalyst can be used over and over again in a chemical reaction: it does not get used up. Enzymes are very much the same except that they are easily denatured (It loses it shape and will not work any more). ...read more.


* Make sure that the end point is fairly determined - As soon as the dot can be seen at least a little bit, the experiment should be stopped. * Make sure the same person does the shaking of the test tube and he shakes it with the same strength in each experiment. * Make sure that only distilled water is used, because tap water may contain impurities, which can affect the results. Safety: * Be careful to not splash any of the solutions as it can be very irritable if the trypsin gets into somebody's eyes * Other than that, follow the basic simple classroom rules PREDICTIONS After carrying out my preliminary studies and also after studying some textbooks, I have been able to make a prediction: As the concentration of the trypsin is doubled, the rate of digestion of the casein in the milk will also double. Therefore, the rate of the digestion of the casein in the milk is proportional to the concentration of the trypsin. This is what I expect the graph showing rate of digestion, against the concentration of the trypsin solution to look like: 0 Conc. ...read more.


This way, the temperature would have stayed relatively the same. Or even better, a water bath could have been used. This would mean that the temperature would stay the same throughout the experiment. To make sure that the measurements of the solutions were, correct, a burette could have been used, which is very precise and would have made the results more accurate. Also, to decide when the experiment was over a light detector could have maybe been used; a would have been shone through one side of the test tube, and when the milk has been digested and it turns translucent, the light detector would indicate this, and my results would have been more accurate. Also, it may have also been a good idea to use some type of stirring device so that the results would have been a bit fairer. The experiment could have been extended by varying the temperature in which the reaction took place. Or I could have also varied the concentration of the milk, and also the pH of the solution. This would have helped me get a more overall understanding of how the enzyme, trypsin works. Even though the results are slightly 'off', I still think I can come to a firm conclusion with them. ...read more.

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