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the effect of bile concentration on the activity of the enzyme lipase during the break down of milk

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Aim To investigate the effect of the concentration of bile salts on the activity of lipase on the breakdown of milk. Introduction From prior AS knowledge involving biological molecule I know that lipids are broken down into fatty acids and glycerol by the action of the enzyme lipase. Subsequently using this information in the experiment we will be measuring the fall in pH using a pH probe to find the rate of reaction of the experiment. This is because if lipase is breaking down the lipids then the pH should fall and become more acidic as fatty acids which are acidic are being produced. By keeping the variables the same except for the concentration of bile salts we can be able to see what affect, if any the bile salts have on the activity of the enzyme lipase on the breakdown of lipids, with our source of lipids being milk. In addition to this by using accurate apparatus and by keeping the conditions the experiment is done in the same I will be able to make my results both precise and accurate. Background Enzymes An enzyme is a biological catalyst that speeds up the rate of a chemical reaction by lowering the activation energy needed by the reactants to react, thus allowing the reaction to precede much faster by a factor of millions as seen in the graph below. Like all catalysts, enzymes remain unaltered by the completed reaction and can therefore continue to function, although unlike other catalysts enzymes are very specific to the substrates they bind to and therefore the reactions they catalyse. Because most of the reactions in biological cells would occur too slowly without the use of enzymes, enzymes prove to be essential to sustain life. Subsequently they are so important that a malfunction (mutation, overproduction, underproduction or deletion) of a single critical enzyme can lead to a severe disease. ...read more.


* Long hair should be tied up during the experiments to ensure that it does not get in the way or come into contact with any of the chemicals being used. * Care should be taken when using glassware to help prevent breakages. * The thermometers should be handled with care and placed in an appropriate position when not in use to ensure they do not role off the desk. * When the experiment has been finished all equipment and desk should be cleaned well to remove any risks of other people being accidentally exposed to the chemicals. * All chemicals should be disposed of in a careful manner and correctly according to what they are. When chemicals are being disposed of down the sink ensure tap is running when putting waste products down there. * Make sure all gloves and tissue used are placed in the bin when finished with. Dilution Method In order to dilute a given solution in a quantitative manner, a known volume of the solution is transferred, via a pipette, to a volumetric flask. Addition of a solvent (usually water) is then added to the flask until the level of the solution reaches the graduation mark on the neck of the flask. The flask is then stoppered (some flasks have plastic caps rather than stoppers) and the contents are then thoroughly mixed. Dilution to 4% 1. Obtain a 100cm3 volumetric flask and move it to your working area 2. Obtain a 20cm3 pipettes and move them to your working area 3. Obtain a 100cm3 beaker and fill it with approximately 90cm3 of the 5% bile salts solution, then take it to your working area and label it 5% bile salts solution 4. Obtain a 100cm3 beaker and fill it with approximately 40cm3 of distilled water, then take it to your working area and label it distilled water 5. Using the 20cm3 pipette, suck into the pipette 20cm3 of 5% bile salts solution and then pour the solution into the volumetric flask 6. ...read more.


Furthermore because the overall trend of the results shows how at higher bile salts concentration the rate of reaction will be higher, we can therefore conclude that the results are reliable since this trend is similar to the trend shown when the substrate concentration is increased in an enzyme catalysed reaction which is what is occurring in our experiment at by emulsifying the fats into smaller droplets the substrate concentration is also being increased. Even though our results had an anomalous result, I don't believe it affected the validity of the conclusion you can draw from the results. This is because the results still show the trend of how increasing the concentration of bile salts increasing the rate of reaction which is scientific knowledge I research for my background suggested. Furthermore by having this trend it shows that bile salts have an effect on the activity of lipase when digesting fats as they seem to increase the rate at which the fats are digested so we can deduce they increase the enzymes activity. The anomalous result we got due to a procedural error is only significant is telling us that there are other limiting factors to the experiment one of them being pH in which case we did not control as effectively causing us to get an error. Additionally even though the method I used had some procedural errors in it I believe that these errors affected the preciseness of the results more than the accuracy making the results only slightly imprecise as the standard deviation shows since it is low. However by taking the average of these results it made our results more accurate than just using one set of results as this set of results could have been inaccurate. Because of this and the fact that for some of the measurements I carried out I used accurate glassware I can say that my results were valid. ?? ?? ?? ?? Planning 1 ...read more.

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