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Speeds enzymes break down proteins

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Speeds enzymes break down proteins My hypothesis for this experiment is that as the enzyme concentration increases, the time taken for the protein to break down decreases. Background Knowledge : The way enzymes work can be described using the lock and key hypothesis. Specific enzymes have specific shapes that fit with the shapes of the things they break down. For example a lipase will only be able to break down lipids, not carbohydrates etc. The milk solution will clear as the trypsin (a protease) enzyme breaks down the casein (a protein) in the milk. The milk will clear because the enzyme is breaking the casein down so that rather than being in long insoluble chains it is in small chunks that can dissolve and produce a clear solution. http://regentsprep.org This means that enzymes are biological catalysts (they speed up reaction rates but don't change themselves). They are globular proteins with a specially shaped 'lock' called an active site. The active site contains amino acids which will only join with certain substrate molecules, the 'keys', to form an enzyme-substrate complex. The enzyme will hold the substrate, and charged groups in the substrate and active site will attract, distorting the substrate and aiding bond breakage as it reduces the amount of energy needed to break the bonds. (The energy needed to break the bonds is called activation energy.) ...read more.


>1800 725.3 402.6 453 395 255 316 191 Rate of reaction : The rates of enzyme-controlled reactions are measured by the amount of substrate used or the amount of product formed in a given time. For this experiment it would be sensible to measure how much product is used up as the volume of the mixture is kept the same throughout making it hard to measure how much product is formed. When comparing the rate of reactions the initial rate of reaction is used. This is at the beginning of the reaction when it is happening rapidly and is measured as 1/T where T is time. So to work this out we must make another table. Final enzyme concentration (%) 0 0.05 0.1 0.15 0.175 0.2 0.225 0.25 Average time taken for solution to clear (s) >1800 725.3 402.6 453 395 255 316 191 Rate of reaction (1/T) >0.0005 0.00138 0.00248 0.00221 0.00253 0.00392 0.00316 0.00524 Analysis : The graph of time against concentration shows a general trend; as the enzyme concentration increases the time taken for the solution to clear decreases. This is most likely caused by an increase in the number of enzyme molecules as the concentration increases, meaning that there are more enzymes for the casein to be broken down by. And as the casein breaks down it becomes soluble and dissolves in the water forming a clear solution. ...read more.


in the time we had (1 hour). There weren't really many safety issues with this experiment, the only thing we really had to be careful of was getting enzyme on our skin or in our eyes as it may trigger allergies or irritate the skin. There weren't really any measures taken to prevent getting the enzyme on our skin, other than safety specs(?) as the risk is so small, even if we did get any on our skin. When we did the experiment we were careful not to drop anything, and we tried our best not to spill any enzyme or milk solution. The method we used to do this was not necessarily the most precise as it was a whole class experiment, to fit it into the time we had, and everyone has slightly different views on when the solution was clear enough. Also for two of our results we only managed to do once for each because we ran out of milk solution. This means that these results are not necessarily reliable, as we could not tell if there was continuity in those results. Conclusion : I think that my hypothesis has had some evidence to support it from my experiment. (It isn't proved as proof is absolute.) The method we used was not very accurate as it relied on different peoples opinions of when the reaction had occurred. It also was not organised particularly well so we ran out of milk solution and therefore could not get a full set of results. However it does give a general idea of what happens. ...read more.

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