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

Membrane Permeability : the effect of temperature

Extracts from this document...


Membrane Permeability : the effect of temperature AFTAB MOHAMMED Membrane Permeability : the effect of temperature TITLE 'How does temperature effect membrane permeability?' METHOD The Investigation was carried out in the following way: * Six pieces of beetroot were cut out about 2 cms long using a cork borer. * The cylinders of beetroot were placed on a white tile and using a razor blade they were cut into discs 3 mm thick. * The discs were placed in a beaker of tap water and washed thoroughly, rinsing out the beaker several times. * Test tubes were labelled for each temperature to be tested. The temperatures required were 30, 40, 50, 60, 70 and 80?c * 6cm� of tap water was put in each test tube * 6 washed beetroot discs were impaled on a mounted needle allowing space between each disc. * Mounted needle with discs was placed in the 30?c water bath for exactly one minute. At the end of this time, the discs were taken off the needle and dropped into the test tube labelled 30?c * This procedure was repeated for temperatures 40, 50, 60, 70 and 80?c. ...read more.


Between 40-50?c, the opposite happens here, my results show that the absorbance decreases but the mean results show that the absorbance increases Between 50-60?c, there was an increase in the absorbance Between 60-70?c, there was a very steep increase in the absorbance Between 70-80?c, there was an increase in both results The difference in the results at the beginning of the graph was probably due to anomalous results. CONCLUSION The graph clearly shows that as the temperature increases, the absorbency also increases. The beetroot discs were washed in the experiment to remove any anthocyonin from the surface. The colour of the liquid in the test tubes changed due to diffusion taking place. Anthocyonin diffused out from the cell into the liquid. This happened because of the big concentration gradient. The results showed that as the temperature was increased the membrane became more permeable and allowed more pigment to enter the liquid from the beetroot. DISCUSSION The cell membrane contains intrinsic proteins that control the membrane's selective permeability. ...read more.


structure. This structure accounts for the cell letting the anthocyonin out. EVALUATION Errors: * Some beetroot may have more anthocyonin than others. This is trivial though; it would not make much difference. * The beetroot discs were not measured as accurately as they seemed. They could be significantly too large or small. * The equipment used was not accurate enough. Using a pipette is not necessarily accurate; it could have produced errors in measurement. Limitations: * The whole experiment should be repeated more times to make the results more reliable * Only 6 temperatures were looked at, we could have done more * When the beetroot was stabbed to put on the needle, it could have allowed anthocyonin to come out. But this was done so that the beetroot discs don't touch one another and maximum surface area is created. * Errors could have been made when using the colorimeter, it as a machine and they can make accuracy errors. * Cuvettes had to be handled very carefully, but scratches may have already been on then and fingerprints also affect the absorbency. So in effect, these could have taken place. AFTAB Mohammed BIOLOGY SALTERS 1 ...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)

    Both the tonoplast membrane and the plasma membrane are made up from a phospholipid bilayer. At 80?C, when the most red pigment has diffused out of the cell, the membranes were at their most permeable. As I explained in my prediction, the membrane is fluid and always on the move

  2. Marked by a teacher

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

    3 star(s)

    If the beetroot is cut, cells are sliced open and the pigment spills out. However, if the membrane is altered more subtly, leakage (diffusion) of betacyanin is induced. I predict that as the temperature increases, the amount of pigment that leaks out will also increase as when the temperature increases that phospholipid bilayer will become increasingly more fluid.

  1. Marked by a teacher

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

    3 star(s)

    It could also be said that the results will be more reliable as a better piece of equipment is used Cutting of discs- not always cutting the beetroot straight and sometimes cutting them vertically, causing the surface are to be different on the beetroot cylinders Always increasing Take extra care when cutting the beetroot.

  2. Marked by a teacher


    3 star(s)

    This is due to the input of kinetic energy due to the build up of temperature that increases the rate of diffusion, and the increase in temperature causes a vibration. This in turn will damage the plasma membrane causing substances contained within the membrane to leak out.

  1. Marked by a teacher

    effect of temperature on beetroot pigment through membrane

    3 star(s)

    my experiment, I will do one more trial on each temperature and get a more accurate average reading. Safety: - Goggles must be worn at all times, whilst Bunsen burners and chemicals (buffer) are being used in the room. - Any loose clothing should be removed, this will minimise spillages and accidents.


    And because once a protein is denatured it can no longer be used by the body as it lacks its necessary structure and as the protein function is dependent upon this, it becomes useless, so the diffusion of the betalain pigment remains constant.

  1. Experiment to show the effect of Temperature on membrane permeability In beetroot

    (See fig 1) This model was widely accepted as an accurate representation of the actual membrane structure found by using the freeze-fracture method under an electron microscope. (Reed 1998) When looking at membrane structure common experiments carried out are to find the effect of external influences to its integrity.

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

    Exocytosis is possible through the cell membrane, but it is a process involving bulk transport, and this is not likely to take place through the tonoplast. After looking at all the possible ways in which the dye could leak out of the cell, it can be certain that the dye

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