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

"An investigation to find out the optimum temperature for the activity of Lipase".

Extracts from this document...


"AN INVESTIGATION TO FIND OUT THE OPTIMUM TEMPERATURE FOR THE ACTIVITY OF LIPASE" * AIM To investigate the effect of temperature has on enzyme activity and the hypothesis that there is an optimum temperature for the activity of the enzyme lipase. * INTRODUCTION Enzymes are catalysts made up are protein molecules, usually with a globular structure. They accelerate chemical reactions in organisms that would otherwise occur to slow. (Green, Stout, Taylor, 1991) Lipase is a digestive pancreatic enzyme which works to hydrolyses fats into glycerol and fatty acids. (Simpkins, Williams, 1987) These products will react with the Sodium Carbonate (put into the mixture to raise the pH) and in effect lower the pH level towards a more acidic content. This pH change can be observed by using the indicator Phenolphthalein, which changes from a pink colour to colourless at a pH below 8.3. * HYPOTHESIS Lipase is an enzyme found in the human body and from knowledge of human enzymes I expect the optimum temperature to be around 40�C. ...read more.


Phenolphthalein is flammable, keep away from naked flames * RESULTS Below is a table of the times it took for lipase to convert enough fats into fatty acids and glycerol to lower the pH below 8.3 so that the indicator would show this. Start Temp (�C) End Temp (�C) Time Taken Rate of Reaction (g/s) 80 76 No change after <25m 60 54 11m 25s 5.3 40 35 11m 35s 5.2 20 20 20m 38s 2.9 21 21 18m 34s 3.2 If the results are put into a scatter graph (below) and a polynomial trend line added you can see the rate of reactions in comparison. At 20�C we can see the lowest ROR at 2.9 g/s, next is the control experiment which was carried out at room temperature 21�C and the ROR was slightly higher at 3.2 g/s. At 40�C the rate of reaction increase noticeably up to 5.2 g/s as the time taken was nearly halved. At 60�C there was a slight increase in ROR than previously with the time taken only slightly quicker. ...read more.


As the kinetic energy increases the lipase molecules starts to vibrate more. At a certain point this vibrating becomes too great and the weak hydrogen bonds that hold the proteins into its structure begin to break. These breaks result in the lipase's structure shape changes, which changes the shape of the active site. With a different shaped active site the substrate will be not fit into it and will no longer be able to form complexes with it. (~~~~~~~~~~) (See fig1) However the ROR is still higher than for 40�C, which shows us that some of the lipase reacted with the fat before it started denaturing. This is because at the rate of denaturing increases as the temperature increases. Denaturing usually takes place in human enzymes between 40�C and 45�C and this can be seen in the graph as ROR begins to slowdown increasing around 40�C. At the top temperature of 80�C there was no change detectable due to the large amount of kinetic energy subjected to the lipase and it had become denatured. There would have been a little amount of reactions taking place but not enough to lower the pH so that we could observe a change. * CONCLUSION ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour 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 GCSE Patterns of Behaviour essays


    be controlled How it will be controlled Volume of bile salt It is important that the volume of bile salt added in the experiment remains the same in all trials and for all concentrations regardless of the change in bile concentration.

  2. Effect Of Substrate Concentration On The Activity Of Catalase

    This will help me calculate an average result (line of best fit on a graph) and also increase the accuracy of my experiments. Evaluating I can improve my method to give me better results by using a wider range of concentration of hydrogen peroxide.

  1. Investigation into the digestion of milk by Trypsin.

    This experiment should then be repeated a further 2 times so that a mean average can be taken from the results, (this should increase accuracy by compensating for anomalies that may occur). The apparatus should then be set up in an identical fashion, except that a water bath at 40 degrees Celsius, then at 60 degrees Celsius should be used.

  2. The aim of the investigation is to examine the kinetics involved in the reactions ...

    87 (2dp) The gradient of the graph is a negative number this represents that the reaction is an exothermic one as bonds are being broken. Experiment 1 a (hydrochloric acid) activation energy calculation The following shows the calculation to calculate the activation energy for the reaction between hydrochloric acid and magnesium ribbon: Activation energy =gradient x R (gas constant)

  1. Health Implications of eating Fat

    Depending on the geometry of the double bond the polyunsaturated fatty acids can assume a cis or trans conformation. They can be divided into two categories Omega - 3 fats which can be found in fish, seafood, and lean meat, plant foods such as cereal grains, seeds, nuts, legumes, dark

  2. Factors Affecting Enzyme Activity

    factors affecting enzyme activity I discovered that there were several different factors, four of which I could feasibly investigate in the school laboratory. These four factors were temperature, pH, concentration of substrate (hydrogen peroxide) and concentration of the enzyme solution (catalase solution).

  1. Investigate the rate of a catalysed reaction, when altering the temperature of the solution ...

    Because there are 23 known amino acids, the number of amino acids in a chain can vary. Amino acids are made of different elements and so they could each have a slightly different charge. 2) Secondary Structure The secondary structure is the folding of the chain(primary structure)

  2. Catalase activity in the liver

    take the temperature at the bottom of the test tube this keeps the experiment a fair test. The reaction that takes place in this experiment is 2H202 2H20 + 02 WHAT DO YOU PREDICT WILL HAPPEN? The way I will prove that the enzymes are the reason for oxygen to be given off (in the form of froth)

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