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

What effect do different concentrations of bile have on the lipase activity?

Extracts from this document...


Problem: What effect do different concentrations of bile have on the lipase activity? Experimental Design: Lipase is a digestive enzyme commonly used in our digestive system. There are several types of lipase including pancreatic lipase (mostly) and salivary lipase. Bile is a solution containing negatively charged bile salt, which separates the insoluble lipid into smaller pieces and kept them small (emulsification). To test different concentrations on the lipase activity, obviously more than one different concentration of bile solution is used and lipase concentration and volume are controlled. To isolate the effects of different [bile] on lipase activity as a single variable, any other variables effecting lipase activity would be controlled. The source of fat is cream and volume/concentration of sodium bicarbonate must be the same in each individual trial. It is entirely possible that different volumes of phenolphthalein would effect the pink intensity of individual test tubes, thus in caution, the drops of phenolphthalein is also controlled. Variables: Manipulated- the concentration of bile in each test tube Controlled- the temperature in which the lab is performed - The concentration/volume of lipase in each test tube - The number of drops of phenolphthalein in each test tube - The volume of total solution - Volumes of cream and sodium carbonate - Concentration of sodium bicarbonate Responding- the time in which the indicator changes ...read more.


18) Repeat steps 5- 9. 19) Repeat step 3 for the test tube labelled 5. 20) Add 4mL of bile into test tube 5. 21) Repeat steps 5- 9. 22) Repeat all steps (1- 21) in order to have 3 replicates of this lab. Table #1: Time Intervals Recorded for the Change of Color of the Indicator of Different Test Tubes. The time interval for three replicates is recorded. Volume of Bile added to Test tube (mL) Time for pink to dissipate (Replicate one)(min:secs) Time for pink to dissipate (Replicate two) (min:secs) Time for pink to dissipate (Replicate three) (min:secs) 1 14:52 19:16 6:57 2 3:25 12:43 7:55 3 3:00 8:43 6:27 4 3:09 2:31 5:50 5 2:19 4:23 5:13 Analysis/Discussion: First thing to be noticed is that the time interval for replicate #1, test tube #1 seems to be out of place when compared to the rest of replicate #one. In replicate #one and replicate #three, test tube #5s are clearly the least time within their respective replicates. According to the procedure, test tube # 5 has the highest bile concentration and according to the hypothesis, it should have the least time. The observations from test tube # 5, both replicate #1 and #3 confirm that. ...read more.


In order to record the time elapsed during each individual experiment, one person must make an interpretation/judgement on when to stop the time based upon his/her ideas. Because of this interpretation, there could be differences of opinions on the time interval between the partners, resulting in an inaccurate recording of time elapsed. 2. A minor source of error could be changes in the substances/materials exposed to air in respect to elapsing time. For instance, some cream is known to change in physical properties (states) when the ambient temperature increases. Assume that the cream used in the experiment was taken out of the refrigerator at a certain temperature, and trial one was carried out immediately, followed by trial 2 and so on. By the time trial #5 is complete, the cream has endured time (which allowed for slight differences of cream) that is not included in trial #1, producing a different cream used in trial #1. The result is some minor difference between trials. 3. The procedure is judged adequate because it is simply to follow and straight forward. 4. Possible improvements for this lab could be that one test use fresh and another test uses an old cream. The purpose of this set of experiment is to test whether slight differences in creams cause any significant differences in the time elapsed. ...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 Aqueous Chemistry 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 Aqueous Chemistry essays

  1. Investigating the effect of a chosen factor on the activity of Lipase

    The Bile salts accomplish this by emulsifying the lipid so that the enzymes will be able to react with them much more easily and rapidly (diagram opposite?) As derivatives of cholesterol, bile salts have both hydrophilic and hydrophobic domains (amphipathic).

  2. Investigation of the carbonate - bicarbonate system

    HCO3- + H+ H2O + CO2 Both methods is used to determine the total alkalinity of the reaction, thus, total alkalinity is the addition of the equivalence points of the reaction. Methodology The experiment was carried out in two parts, titration and pH indicator methods.

  1. Investigating the Effects of Increasing Copper Sulphate Solution Concentrations on the Germination of Cress ...

    The 60mg/l and 0.06mg/l test: The t value was 16.9 and the degree of freedom was 14. This meant that I had to find the probability using the following column of the t distribution table: Decreasing value of p Degrees of freedom (df)

  2. Investigation to determine the effect of different sugar concentrations on Benedict's solution.

    The thermometer will be required to measure the temperature and also make sure that the same temperature is used for all solutions. The distilled water will be used along with the Glucose to make a 10% sugar solution, which will be discussed in the method.

  1. Test the hypothesis that lipids have special properties inrelation to solvents.

    the oil dissolve in the alcohol but a dark red colour formed at the bottom as most of the lipid that did not dissolve fell to the bottom since ethanol is more dense than oil. Explanation of method 3 This test is a test for lipids.

  2. The action of lipase.

    With a graduate pipette 1 cm3 unboiled lipase solution is placed in test tube 2. 6. With a graduate pipette 2 cm3 unboiled lipase solution is placed in test tube 3. 7. With a graduate pipette 4 cm3 unboiled lipase solution is placed in test tube 4.

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