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

Beetroot Experiment. The purpose of this experiment is to determine the effect of temperature on the permeability of cell membranes

Extracts from this document...


2.1 Effect of Temperature on Membrane Permeability Abstract The purpose of this experiment is to determine the effect of temperature on the permeability of cell membranes. As beetroot cell contain a coloured pigment within the cell vacuole called betalain. The leakage of the coloured pigment betalain out of the cell will act as a maker to determine how permeable the cell membrane is at a particular time. To determine the permeability of the membrane uncooked beetroot cylinders will be bathed in water and exposed to different temperatures. The water in which the beetroot has been bathed in will then be measured for is absorbency. Here I demonstrate that there is a positive correlation between temperature and membrane permeability. Introduction Membranes consist of a phospholipid bilayer; this is two layers of phospholipids facing in opposite directions to each other. A phospholipid molecule is made up of a phosphate head connected to a lipid tail3. The phospholipid head orientates itself so that faces the external environment or inwards into the cytoplasm. The non-polar tails are hydrophobic and as a result face inwards to the centre of the plasma membrane4. Figure 1 shows the phospholipid bilayer arranged so that the hydrophobic (water hating) tails are orientated in the middle and the hydrophilic (water loving) heads are facing outwards from the cell1 The Plasma membrane is not rigid and in fact the phospholipid molecules are fluid in that they can move laterally and diffuse, the addition of cholesterol to the cell membrane improves the fluidity if the membrane. In addition to the phospholipids found in the membrane there is a large amount of protein present6. There are two major groups of proteins found associated with the plasma membrane. There are the proteins which are adjacent to the membrane known as peripheral proteins. The second group is the integral proteins which are embedded into the membrane7. Figure 2 shows the complex structure that is the plasma membrane. ...read more.


(Highest being 10 lowest being 1) Risk Probability Severity Being cut by glass/scalpel 7 6 Being scolded 7 7 Slipping/tripping 4 8 How the probability of these risks can be reduced Being cut by glass/scalpel- be extra aware of these dangerous objects, if glass is smashed get it cleared up safely immediately. Use a suitable cutting surface and cutting mat when using the scalpel and put a protective cover over the blade when walking with it. Being scolded- take care when around hot water baths and know where nearest cold tap is and make it easily accessible. Use tongs when collecting test tubes from the water baths. Slipping/tripping – before I start I will check the room and check there are not any obstructions on the floor (i.e. bags etc). If water is spilt on the floor I will make sure it is cleared up immediately so the floor is not slippery. Results Temperature (°C) Absorbance (from colour Chart) 1st Experiment 2nd Experiment Average 0 0.24 0.24 0.28 15 0.22 0.24 0.25 30 0.30 0.28 0.30 50 0.58 0.55 0.52 70 0.78 0.75 0.78 90 0.80 0.82 0.80 A mathematical calculation can be carried out on this experiment to see if there is a correlation between the temperature and one of the readings in the results; transmission or absorbency. If there is then it is possible to accept or reject our original hypothesis. For this calculation I will be using transmission, as it is an easier figure to use being larger, the average data will be applied to the calculation to get a more accurate result. The hypotheses remain the same from the main experiment found earlier in the report. Data Table: Spearman's Rank Correlation Experiment Temperature Rank temperature Average absorbance Rank Absorbance Difference between ranks (d) d² 1 0 1 0.28 2 -1 1 2 15 2 0.25 1 1 1 3 30 3 0.30 3 0 0 4 50 4 0.52 4 0 0 5 70 5 0.78 5 0 0 6 90 6 0.80 6 0 0 d² = 2 1. ...read more.


This makes any predictions on the results less accurate as you are using quite large temperature ranges. I would have liked to repeat each of the temperature results a third time as I believe that an N=2, is not very significant to base any finding on. I think a third set of results would have been more significantly valid. A major limitation is the actual manner in which the segments are obtained. Although I was careful in trying to obtain segments of the same size and cross sectional area they will never actually be the same. If the surface area of the segments differ only slightly this will have an effect (if only slightly) on the amount of Betalain that can leave the cell through diffusion. It would also have been a good idea to actually check this effect in other cells, from other species and plants and possibly animal cells (although the availability of such may have been limited and the practical methods to identify breakdown of the plasma membrane been difficult). I believe that having results form other species of plants would dramatically improve the accuracy of any conclusions made. Overall I believe that the results of this experiment are valid but there are several practical errors that limit the accuracy of the conclusions based upon it. Cold-induced leakage of amylase from the zymogen granule and sealing of its membrane by specific lipids 1. http://biologyatsmc.wikispaces.com/Cell+Membrane 2. http://www.colorado.edu/intphys/Class/IPHY3730/03plasmamembrane.html 3. Kimball's Biology Pages, Cell Membranes 4. Alberts B, Johnson A, Lewis J, et al. (2002). Molecular Biology of the Cell (4th Ed.). New York: Garland Science. ISBN 0-8153-3218-1. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.section.1864. 5. Singer SJ, Nicolson GL (Feb 1972). "The fluid mosaic model of the structure of cell membranes". Science 175 (23): 720?31. doi:10.1126/science.175.4023.720. PMID 4333397. http://www.sciencemag.org/cgi/content/abstract/175/4023/720. 6. Lodish H, Berk A, Zipursky LS, et al. (2004). Molecular Cell Biology (4th ed.). New York: Scientific American Books. ISBN 0716731363. 7. Jesse Gray, Shana Groeschler, Tony Le, Zara Gonzalez (2002). "Membrane Structure" (SWF). Davidson College. http://www.bio.davidson.edu/people/macampbell/111/memb-swf/membranes.swf. Retrieved 2007-01-11. ________________ UCI 205340050507X Candidate Number 0507 NEC student number SS121598Page ...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

Here's what a teacher thought of this essay

4 star(s)

This is a good account of the investigation. The discussion and evaluation are of a high standard with good use of A level terminology. In other places, however, there could be more attention to detail and more detailed explanations. The author does not seem to be sure how to identify independent and dependent variables.

Marked by teacher Adam Roberts 17/09/2013

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

    Analysing the vitamin C content in different fruit juices

    5 star(s)

    Owe to this reason, the gradient of the graph is negative. This graph can also be known as standard curve. It enables us to determine the exact concentration of vitamin C in fruit juices. Table 2 shows the volume of fresh fruit juices needed to decolourise 0.5ml of 1% DCPIP solution.

  2. Marked by a teacher

    The Effect of pH on Pectinase

    3 star(s)

    Pilot Experiment Our Pilot experiment took place on Wednesday 27th February. In my pilot experiment I experimented with a range of Buffer solutions at pH3 to pH7 in a water bath set at 40 C and used sand as my control.

  1. The Effect of Concentration on Pectinase Using Apple

    The test tube is then placed in a 40�C water bath for exactly 20 minutes. Meanwhile a 5ml measuring cylinder with 0.1ml intervals, filter paper, and funnel is set up to collect the apple juice produced from the pulp. After 20 minutes, the test tube is removed from the water


    At low temperatures e.g. 0�C to 35�C, some tonoplast (vacuolar membranes) and the cell membrane will leak into the surrounding water but at a much higher temperature, the tonoplasts of the cells will break down completely, resulting in a massive release of betalain pigments.

  1. Planning an experiment into the effect of mouthwash on bacteria

    Chlorhexidine is highly used in mouthwashes, as it is an antiseptic and disinfectant agent. It is active against various bacteria, viruses, bacterial spores and fungi. It kills the microorganisms associated with various mouth and throat infections as well as other common conditions in the mouth.

  2. Investigating the effect of temperature on the activity of free and immobilised enzymes.

    * The test strip was left for 2 minutes before the colour change was compared and the result recorded. This was repeated 3 times at each temperature. The starting temperature was 30?C and the temperature was increased by 5?C increments up to 60?C.

  1. Permeability of Cell Membrane in Beetroot Cells

    The pigment in the beetroot cells is called anthocyanin. It is contained in the vacuole of the cell so when the cell is ruptured, the contents diffuse out. The pigment leakage is caused by diffusion. The more pigment that leaks out this indicates a greater the rate of diffusion.


    There is no mechanism in plants to prevent excess water loss in the same way as excess water gain, but plasmolysis can be reversed if the cell is placed in a weaker solution. The equivalent process in animal cells is called crenation.

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