• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12

Find out if enzymes work faster or slower at different temperatures.

Extracts from this document...


Nick Spong Biology 10/11/03 Introduction This is the plan and evaluation of an experiment to find out if enzymes work faster or slower at different temperatures. We will be timing how long it takes to see a cross through 20cm3 of Marvel milk solution at three different temperatures. We will be using the enzyme neutrase to break down Marvel milk. Hypothesis My hypothesis (theory) is that at temperatures over 40�c the neutrase will be increasingly denatured and the milk will not clarify. Under 40�c the neutrase will be slowed down. However I predict that at 40�c the neutrase will be working well as this temperature is near its optimum temperature and so the milk will decolorize the fastest. I have made my prediction based on the following evidence: The reason that the milk will decolorize or do anything at all is because neutrase is an enzyme. Enzymes are biological catalysts. This means that they are a biological life form that catalyses (speeds up) a process. They have an optimum temperature and pH. Both of these have to be almost exactly right, otherwise their performance deteriorates rapidly. In high temperatures the enzyme will be denatured and will not work even if you bring the temperature back down. However, at low temperatures, and low and high pH's, all you have to do is bring the environment close to the enzyme's optimum environment and the enzyme will work again without any loss in performance. We will be using a 2% solution of neutrase, this means it is 98% water. If we increased the concentration we would be increasing the amount of neutrase and it would have exactly the same effect as increasing the volume of the neutrase and water solution. Overall the reaction would be faster as more particles mean more collisions. So if we increase the amount of enzymes in solution, we will have more collisions of enzyme and substrate and then the substrate will break down into the products faster, so we must keep the concentration constant to make the test fair. ...read more.


We will record our results to the nearest hundredth of a second as this is the smallest amount of time that the stop clock will display. To make sure the test is fair we will: Use a buffer solution to make sure the pH is the same for all of the experiments. Try and measure accurately and with the same equipment for each of the experiments. The concentration of both will need to be the same but we cannot do anything to control this as we will be given the solution of milk and neutrase and will not be involved in any way in creating the 2% solution. We will use the same person to judge when the mixture is decolorized, as a different person could have worse/better eyesight than the other and this would result in inaccurate results. To keep the temperatures as near to the target temperature as possible, we will leave them in the water bath/ice tray for the same amount of time. We will repeat all 5 experiments 3 times and then get rid of all obvious anomalous results. Only when we have results that seem consistent will we take the average figure and use this as a final result. Make sure we wash all of the equipment before we start the next test. We will change the variable so we readings at 10, 35, 40, 60 & 80oc. Each reading will be taken 3 times. Some safety precautions I will need to take are: Wear goggles to protect my eyes. Wear gloves to protect my hands Do not sit down. Do not run with chemicals or glass. Do not eat or drink whilst in the lab. When we have collected the results in a table we will analyze them and then present them in a graph and a table. Results Table Temp. (oc) Actual Temp (oc Enzyme) Actual Temp (oc Marvel Milk) ...read more.


We will then begin the experiment. We will repeat the experiment at 1 degree intervals from -10oc to 100oc we will do each 1o interval experiment 5 times. We will then discard any anomalous readings and take an average of the readings left. We will place the cuvette into the colorimeter and put a funnel into the cuvette. We will then go to collect 1cm3 of Marvel Milk using a 1cm3 gradated pipette. We will then collect a 0.1cm3 solution of enzyme using a 1cm3 syringe with 0.1cm3 graduations. With a different syringe we will collect 0.1cm3 of a pH 7 buffer solution. We will use such small amounts as the cuvettes for the colorimeter are very small and cannot hold much liquid. We will then use a data logger with two probes to check the temperature of the enzyme and substrate before adding them together with the buffer solution into the cuvette. Once they are in the cuvette we will put the cuvette with the reactants into the colorimeter (which will already have a sample of the solvent, water, in it) and at the same time start a stopclock. We will then see how long it takes for the colorimeter to read 95%. Once it reads 95% we will stop the stopclock and take down a reading off of the stopclock. We will then put the cuvette in for washing and take out another cuvette. We will then wash out the graduated pipette and the syringe ready for the next experiment. We will use the same water in the colorimeter to make sure that that does not add another possible error. To get our results we will be measuring how long it takes for the milk to decolorize at 1o intervals between -10 and 100oc. This will give us an idea of the enzymes reactivity. I expect that the results would put the enzymes optimum temperature at around 37oc. Any higher or lower and the overall time will go up due to the enzymes being denatured or the energy being taken away. ...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

Here's what a teacher thought of this essay

5 star(s)

This is a well structured and detailed report.
1. The background section is well written, although the sources of information need to be referenced
2. The preliminary section sets up the investigation well
3. The conclusion uses data and explains the results
4. The evaluation shows a good understanding of scientific practises

Marked by teacher Luke Smithen 17/09/2013

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. Marked by a teacher

    Beetroot Practical Write up

    3 star(s)

    Colourimeter: The colourimeter is precise, reliable and accurate compared to a natural eye test comparison or a colour chart comparison. Statistical figures are given as percentage of transmission of light through the substance. This also gives a more accurate reading instead an eye test or colour test comparison.

  2. Marked by a teacher

    How does the pH affect the activity of amylase

    3 star(s)

    was a rush to get the experiment started as it did take along time so I was not as accurate as I should have been when making the buffer solution. Since the buffer solutions needed to be accurate this could have affected some of the experiment when looking at pH

  1. Qualitative tests for carbohydrates

    sulphuric acid, water * 1 cm3 teat pipette * Test tube rack * Tripod and Gauze * Test tube tongs * Goggles Table Of Results for the qualitative tests carried out on various sugar solutions Table of Results Test Molisch test for Carbohydrates Benedict's test for Reducing Sugars Seliwanoff's test

  2. An experiment to test the effect of different temperatures on the permeability of cell ...

    transmission would drop by 3.0%, which is of a much greater magnitude in gradient. The graph at this part has a much steeper gradient than the earlier part of the graph, this means that for the same amount of change in temperature, there is a greater change in the % light transmission that before.

  1. The Action of Lipase and Bile Salts On Milk

    According to these results the optimum temperature appears to be approximately 30 degrees as at this temperature the rate of enzyme action was fastest. The bile salts were used to speed up the reaction. They physically break down the large fat molecules in the milk into smaller molecules which have

  2. The digestive system

    Hydrochloric acid combines with pepsinogen to form the enzyme called pepsin. Pepsin digests only protein. Mucin is a secretion which protects the stomach from being dissolved by hydrochloric acid.

  1. An experiment to find of the isotonic point of root vegetables cells in contents ...

    Also will be used label the water and 1Molar sucrose solution beakers. This will prevent my results from becoming mixed up. Will also be used to label the pipettes. * Scalpel- This will be used to cut the root vegetable to the accurate and appropriate length, this will minimize the

  2. Colorimetry Experiment - I will investigate and observe the amount of concentration of food ...

    is safe as it is below the safe limit which is 18ppm, so therefore there are no further actions that needs to be taken as I have proved my experiment. Evaluation There were many method and experiment problems that came up while doing my colorimetry experiment.

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