• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

I aim to investigate the enzyme Tripsin, and the factors that affect the rate at which it hydrolyses proteins.

Extracts from this document...


Biology Coursework Introduction I aim to investigate the enzyme Tripsin, and the factors that affect the rate at which it hydrolyses proteins. Tripsin is an enzyme that acts in the small intestine of mammals. It is secreted by the pancreas, in the pancreatic juice. This suggests some things that may be important when conducting the experiment. Firstly, it suggests that the optimum temperature for Tripsin would be around the body temperature of mammals, i.e. just below forty degrees centigrade, and secondly, it indicates that the optimum pH would be about 8. This is because pancreatic juice contains sodium hydrogencarbonate, so that the acid from the stomach is neutralised. The pH of the environment in which the enzyme is working affects the enzyme in two ways; the hydrogen ions interfere with the attraction between the enzyme and the substrate, so each enzyme has a specific pH at which the concentration of hydrogen ions is just right for the maximum attraction between the molecules. But the pH also can break the twist and misshape the bonds in the enzyme molecule, thereby misshaping the active site, and so denaturing the enzyme. Therefore, the graph of enzyme activity against pH is usually a bell shaped curve. The temperature affects enzymes in a similar way, but with different consequences; the higher the temperature, the faster the molecules move, and therefore, a higher temperature means more collisions between the substrate and enzyme. However, high temperatures can permanently deform the enzyme, so the optimum temperature is the maximum temperature before the enzymes start to be denatured too much. The graph below demonstrates this:1 Rate at which enzyme activity decreases due to denaturation Enzyme Activity Speed of substrate (heat) Temperature This displays the idea that as the temperature increases, the number of collisions between the enzyme and the substrate increases, but so to does the rate at which enzymes are being denatured. ...read more.


4) Then I repeated this process of checking if the film has gone clear every ten seconds until it went transparent. It did not gone clear after six minutes, so I recorded this on the results sheet as more than six minutes. I made sure throughout the experiment that I did exactly the same thing each time I took out the film. 5) I then mixed up more test tubes replacing the pH 3 buffer with pH 4, then 5, 6, 7, 8, 9 and 10, and carried out the experiments with each different pH 6) I found that I could conduct two or more experiments at once, without losing any significant amount of accuracy, and so decided that in the given time it would be better to do the each experiment twice, while doing two or three experiments at once. 7) After one experiment, I noticed that the result was very different to what I expected, and the result I had got in a previous experiment with similar conditions, so I repeated it. When I had completed this set of experiments, and was confident of the accuracy of my results, I still had some time to investigate further into the workings of the enzymes so I decided to explore the effects of ions other than those found in the acid or alkali. Therefore, I decided to test what would happen if I added salt to the solutions, and see if these ions interfered in any way with the enzyme-substrate bonding. I mixed 1cm3 of saturated salt solution with 0.5cm3 of pH8 buffer, and 0.5cm3 of 4% Tripsin solution, so that I had a 1% solution of Tripsin. I also mixed a test tube with 1cm3 of pH8 buffer, and 1cm3 of 2% Tripsin solution, and placed both of these in the 51oC water bath, and carried out the experiment as above, taking car to do exactly the same thing to each test tube. ...read more.


Further Work As I have said above, if I were to repeat the experiment, I would try to improve the overall accuracy. I would do this by using a more accurate method for measuring the solutions, such as with a glass pipette. I would also try to find a way so that I could check on the film more frequently than every ten seconds. If I took it out every five seconds, then I would be faced with the problem that I would have to take the film out of the water up to twenty times, and so might introduce another error. I think that the best way would be to conduct the experiment in a transparent water bath, so that I could continually monitor the film without taking it out of the bath. If glass water baths have not been invented by the time I come to repeat this experiment, I could set up some sort of hi-tech solution, such as an underwater video camera, which would allow me to watch the piece of film in technicolour, as it is slowly hydrolysed away, and so record the exact time at which it goes transparent. This would cut the margin of error from 10 seconds to around 1. I would be interested to investigate the effects of adding salt solution, when the buffer is at different pHs. I would repeat the experiments that got me the results about the effects of salt solution on the rate, but instead of using pH 8 buffer, I would try other pHs. This would give me data about the combined effects of pH and salt solution, and so would help me to understand the effects of salt solution further, especially if I could compare the results of different pHs with and without salt solution. I do not think that all pHs would be affected in the same way. 1 Toole and Toole Understanding Biology 2 Advanced Biology by W R Pickering 3 Toole and Toole - Understanding Biology Hector Guinness 03/05/2007 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Molecules & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Molecules & Cells essays

  1. Peer reviewed

    As protein denaturation can be cause by several factors such as temperature, pH, salt ...

    3 star(s)

    This interaction included hydrogen bonds, ionic bonds and disulphride bonds. But in some extreme condition, such as high temperature, extreme pH, high salt concentration, the protein will be denaturate. It is because the cross linkage had been broken, the secondary and tertiary structure are alter.

  2. The aim of the experiment is to investigate the effect of temperature on the ...

    Trypsin is used in the digestion system, therefore it would need to work best at around 37 �C (Body temperature). If I had tested trypsin at 37 �C I may have got a slightly shorter time. Enzymes react with temperature in a very complex way.

  1. Investigating the effect of pH on the activity of an enzyme.

    * Collect all the apparatus needed: test tubes (6), test tube rack, photographic film, pH buffer solutions of pH 2,3,4,6,8, protease solution, colorimeter and cuvettes, measuring cylinder and pipette. * Rinse out all apparatus to reduce inaccurate results and contamination.

  2. Investigation of the effect of adding different concentrations of NaCl to an enzyme-substrate (amylase-starch) ...

    Using the syringe provided in the NaCl solution test tube, add 3cm� of the NaCl solution to be tested into the test tube with the 2cm� of starch in it. 15. Label this test tube with the concentration of the NaCl solution used, i.e.

  1. An Experiment to investigate the factors that affect the Power Output of a solar ...

    In this form, silicon is a poor conductor. However, impurities can be added to it to alter this characteristic. When energy is added, in the form of light, a few electrons break free of their bonds and leave their atoms, leaving a hole behind.

  2. Investigate how concentration of the enzyme catalase in celery tissue alters the rate of ...

    This meant that not all of the solution from the syringe went to the bottom of the conical flask, so not all of it reacted, and was left on the underside of the rubber bung and inside the hole. The hole through the rubber bung had no air/liquid pressure applied

  1. A Level Biology revision notes

    Fab fragment of B cell * This produces a short and weak response * T helper cells are required to trigger the true potential of B cells o Once activated, the B cell grow and produce many clone cells o Clone cells have the same Fab fragment that recognizes the

  2. for this experiment my main aim is to investigate the effect of temperature on ...

    But even raising temperature of cells is not enough to give most substrates the activation energy which they would to need to change into products. We cannot raise body temperature much more than this, as temperatures above about 40oC begin to damage too many of the molecule from which we are made, especially protein molecules.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work