• 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 how temperature affects membrane permeability.

Extracts from this document...


An investigation to find out how temperature affects membrane permeability. This Problem What we will hopefully try and find out in this investigation is if temperature affects the permeability of a beetroot membrane Hypothesis As the temperature in which the beetroot is put in increases there will be more red dye diffusing out of the beetroot due to the denaturing of the proteins in the cell membrane as a result of the high temperatures. Background Knowledge The cell membrane can be represented as the fluid mosaic model as shown below. It is selectively permeable and controls what enters and exits the cell. It does this by proteins, however small lipid molecules, non-polar molecules and small water molecules can enter and exit the cell straight across the membrane through the phospholipids, due to the properties of the molecules enabling them to do so. Extrinsic and intrinsic proteins in the cell membrane help other the molecules enter or leave the cell by either facilitated diffusion or active diffusion. Different proteins are specific to certain molecules hence the cell membrane being selectively permeable. Here is a diagram of the cell membrane: As you can see the cell membrane is made up of a phospholipid bilayer which the extrinsic and intrinsic proteins span through. Some of the extrinsic proteins act as antigens for cell recognition with a carbohydrate attaching to then forming a glycoprotein. ...read more.


used to place the solution of the three red pigments in Pipettes Are used to put the red pigment from each boiling tube into each cuvette: Colorimeter This is a piece of digital equipment that measures optical density (light absorbency) in Arbitrary units. This is what tells how much red pigment has been lost by the beetroot This coursework from www.coursework.info Test tube racki Used to put the boiling tubes in when using the colourimeter Diagram of equipment Plan The variable that will be changed in this experiment will be the temperature of each water bath. The steps of each measurement will be 30, 40, 50, 60, 70, 80, 90 and 100 degrees centigrade. I have chosen these steps because I have predicted that 40 �C will be the optimum temperature for the beetroot and will indicate little red pigment diffusing out of the beetroot therefore showing if the cell membrane has kept its integrity. Referring to my prediction 30 C should show the temperature being to low for the proteins to work properly, and as a result show little permeability in the cell membrane. The other temperatures beyond 40�C will show the beetroot being denatured, with more red pigment as the temperature increases, diffusing into the distilled water. I will change the temperature by heating up the glass beaker, which contains water acting as the water bath and the 3 boiling tubes containing distilled water, to the desired temperature using a Bunsen burner. ...read more.


When cutting up the pieces of beetroot in the first place the membrane of part of the beetroot will be broken resulting is red pigment being lost. This acts as excess pigment, which we do not want to measure and therefore we would need to get rid of it. The best way of doing this is the rinse each piece of beetroot that you have cut under distilled water, this will get rid of that excess pigment and therefore you will only measure the red pigment that has been lost in the boiling tubes. Keeping an eye on how long the beetroot is in the water bath for is also important, as already stated earlier in the plan. Making sure that you don't get any finger marks on the cuvettes when using the colourimeter is also important because if any marks get on the clear sides of the cuvettes the cuvettes will be darker and therefore more light will be absorbed. Also making sure that you read the reading of the thermometer at eye level will make sure that you record the reading correctly. I will do 3 replicates for each measurement i.e. there will be three boiling tubes in a specific water bath. Doing this will enable me to take and average of all replicates and therefore discounting any anomalous results. Abid Zaman ...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. Marked by a teacher

    Investigating the effect of temperature on the movement of pigment through beetroot cell membranes.

    4 star(s)

    The structure of a membrane is known as the fluid mosaic model. Fig. 1 and Fig. 2 below show this model in detail. 'Fluid' refers to the fact that the phospholipid molecules and proteins move around within their layers bouncing off one another at a great speed.

  2. Marked by a teacher

    Beetroot experiment. Aim: To investigate how the temperature affects the permeability of beetroot cells ...

    3 star(s)

    * Now check the reading and note it down, this is the absorbency of the dye solution at that particular temperature. * You must do all the above again for each temperature that you are experimenting. Results Conclusion From the table of results that i have collected and the graph

  1. Marked by a teacher

    effect of temperature on beetroot pigment through membrane

    3 star(s)

    Colorimeter: this is an electronic apparatus that measures the light transmission percentage, the higher the reading the less pigment in the specimen. Test tubes with specimen should be cooled before placed into the colorimeter to obtain a more reliable reading.

  2. Marked by a teacher

    Effect of different temperatures on the permeability of beetroot cell membrane.

    3 star(s)

    For example if you look at my average absorbance graph at 25?C the absorbance is 0.35, and at 35?C the absorbance is 0.53. So there is an increase in absorbance. A cell membrane is made up of many different molecules these include phospholipids, cholesterol, proteins, glycolipids and glycoproteins.

  1. Marked by a teacher

    An investigation to examine the effects of temperature on membrane stability in beetroot, by ...

    3 star(s)

    Depending upon what is within the R-group of the side chain of an amino acid, the amino acid can have one of four properties: acidic, basic, hydrophilic or hydrophobic. Acidic R-groups donate H+ ions, whereas basic R-groups will receive H+ ions.


    blocks some of the holes in the cell membrane and therefore slows down the release of betalain. From the results, I found out that low temperature don't affect the membrane of a beetroot in comparison to high temperature which result in more leakage of the betalain pigment.

  1. Permeability of Cell Membrane in Beetroot Cells

    A lab coat and goggles should be worn at all times. The beetroot's pigment is a crimson/mauve colour and stains deeply if it comes into contact with material; therefore the lab coat prevents the pigment from staining your clothes. The pigment that seeps out of the ruptured cells is called anthocyanin.

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

    Cuvettes have unique and accurate shape, size and volume, and their sides are very transparent, reducing the amount of light being absorbed by the cuvettes to be a minimum and have a good accuracy. -Scalpel is used to cut the ends of the beetroot so that they are even and that each pieces are the same.

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