• 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...

Introduction

"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.

Middle

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.

Conclusion

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

  1. Investigation into the digestion of milk by Trypsin.

    Once results and repeats for all four temperatures have been taken the findings can be formed into a graph, (showing the relationship of temperature against the rate of reaction at 20, 40 60 and 80 degrees Celsius), which will highlight trends in the results, making a conclusion easier to form.

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

    The ethanoic acid (weak acid) partially dissociated, so there were fewer hydrogen molecules to react with the magnesium ribbon. Le Chatelier's principle can bring balance to the argument in that " The position of the equilibrium shifts in direction which opposes the change in the conditions".

  1. THE EFFECT OF BILE SALT ON THE ACTION OF THE ENZYME LIPASE

    products, this energy must also be increased to bring the reactants closer together for collision, as shown in figure 2.1. Figure 2.1 Adding Enzymes on the other hand, decreases this activation energy, and at the same time increasing the collision between the reactants, hence increasing the rate of reaction, as

  2. 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

  1. Factors Affecting Enzyme Activity

    If I were to conduct an experiment to investigate the affects of temperature on the rate of enzyme activity I would use a controlled amount and concentration of both reactants, I would make the reaction take place in a boiling tube which rested in a water bath maintained at a specific temperature.

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

    caused by the hydrogen ions in the amino acids. The hydrogen ions can attract the opposite charge, building hydrogen bonds between the amino acids, causing the chain to fold. 3) Tertiary Structure This structure is known as the globular structure.

  1. Catalase activity in the liver

    So the enzymes in this part of the experiment will take no place in this part of the experiment. In the other test tube I will heat 2ml of stock solution to 40?C this is because I have found out at this temperature enzymes work the quickest.

  2. Effect Of Substrate Concentration On The Activity Of Catalase

    0 0.63 1.65 1.71 2.22 2.97 3.26 All the times are in seconds. The average results are all written down to one decimal place because although the stopwatch gives results to two decimal places it is impossible to get accurate times to two decimal places due to the fact that

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