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To investigate the effect of ph on the activity of trypsin.

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To investigate the effect of ph on the activity of trypsin Introduction: PH can alter the rate of reaction because if the pH is too high or too low for the enzyme, it will become denatured, where the structure of the enzyme is changed so that substrates will no longer be able to fit inside the enzyme and therefore will not be digested. Most enzymes work best at pH 7, although some enzymes in the stomach work best in very acidic conditions (pH 1 or 2). The enzyme in my investigation (trypsin) works best between pH 8 and 9, because it works in the stomach which is slightly alkaline as pancreatic juice is present in the stomach which is alkaline. Temperature can alter the rate of reaction because enzymes work best at 37�C and if the temperature is lower then the molecules will move slower and therefore there will be less collisions of enzymes with substrates and the rate of reaction will be slower. If the temperature is higher than 37�C then the enzymes may become denatured and they will not work properly, slowing down the rate of reaction or if the temperature is high enough to denature every enzyme, no reaction will occur. ...read more.


The ph is there to act as the concentration and the trypsin is the substrate * Place the boiling tubes on to a boiling tube rack * Cut up 5 pieces of photographic film all being the same size at of 1.5 cm by 1.5cm * Place the boiling tubes in the heater and leave them for a few minutes so that they can get to the right temperature * Drop the photographic film into the boiling tube and start the stop clock * Keep shaking the boiling tube until the gelatine has disappeared and record the time. You know when the gelatine has been digested because the black part of the film will have disappeared * Once one time has been recorded keep the stop clock going and just write down the time keep this process going until all 5 times have been recorded Safety: As well as the experiment needing to be a fair test, it must also be a safe test for it to be successful. I must make sure that safety goggles are worn at all times in the experiment as trypsin would be very damaging if it got into the eye as it breaks down protein and most of the eye is made of protein. ...read more.


It is not perfectly clear in many cases if the acetate is clear or not, and it is hard to tell. This will be a problem unless another way of is found to stop the clock. One way which would make the stopping of the clock at the right time would be to use a light on one side of the test tube and a light sensor on the other side of the tube connected to a stopclock. When the light sensor detects light through the acetate when it is clear, it would stop the clock. This would eliminate the problem of human error in stopping the clock at an incorrect time. Although there will be slight inaccuracies in my results, the basic shape of the graph is definitely quite clear. The graph shows that as the pH increases from 6 to 9 the rate of reaction increases and as the pH increases from 9 to ten the rate of reaction decreases. I could make my results even more clear by using more pH values, I could use from 3 to 12. I could try mixing an even quantity of two consecutive pH values to gain a midway pH value. This would give me much more accurate results and any anomalous results would become much clearer and I could re-do them and hopefully gain a more accurate result. ...read more.

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