• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4
5. 5
5
6. 6
6
7. 7
7
8. 8
8

# the effect of temperature on membrane permeability

Extracts from this document...

Introduction

Investigating the effect of temperature on cell membrane permeability To investigate the effect of temperature on cell membrane permeability, I am going to use beetroot due to its pigment properties. The pigment is a strong colour, which means that I can easily measure, using a colorimeter, how much pigment is released at certain temperatures. During this practical, I will need to apply controls and a variable. The variable being temperature, and the controls being: * Disc thickness * The amount of water used when heating * The measure of solution put into the cuvette * The time temperature is maintained If these factors were not controlled, results would be likely to produce false reading, due to too many variables. Apparatus Cuvette Colorimeter Beetroot disc Water bath Beaker Tripod Bunsen burner Boiling tube Cork borer Forceps Safety glasses Thermometer Stop clock Scalpel Pipette Method 1. Put on safety goggles as a safety precaution 2. Switch on colorimeter to allow it to warm up and stabilise, ready for when it is needed 3. Prepare living specimen of beetroot using core borer, to get small discs of the same diameter 4. ...read more.

Middle

Exy is Ex multiplied by Ey (20*98)+(35*94)+(45*81)+(55*75)+ (65*59)+(75*27)+(85*17)+(95*16) i.e.: the temperature multiplied by the result. Sxx = Ex2 - (Ex)2 /number of results i.e.: 8 Syy = Ey2 - (Ey)2 /number of results i.e.: 8 Sxy = Exy - ((Ex)(Ey) /8) The PMCC demonstrates that the results show a very strong positive relationship between temperature and light transmission. Likewise, the graph also shows a positive correlation - a pattern that quickly became apparent early in the investigation. As the results show more beetroot pigment can leak out at higher temperatures, I can construe that cell membrane becomes more ruptured as temperature increases. This brings me to conclude that in beetroot, as temperature increases, light transmission decreases. This means that the more betalaine (beetroot pigment) is released at higher temperatures, making the solution more concentrated, allowing less light transmission. Why use a colorimeter? A colorimeter entails a light source, a filter to select the most appropriate wavelength, a photocell to interpret the light intensity and a digital display. A colorimeter gives the percentage of light which can pass through the solution. The most suitable filter to use can be selected by choosing the one with the closest colour to match that of the solution being tested. ...read more.

Conclusion

Marginal variance regarding temperature may have caused small anomalies, as seen in the table for test 1 (85 oc, 14%). Another problem which would have proved to have affected the results is the technique by which the beetroot discs were cut. The discs were hand cut, which means that they are not all of uniform size. For this reason, the amount of pigment in each disc will not be consistent either. A natural variation of the pigment contained in each disc will influence my results further. If one disc of beetroot contains more pigment than the next, then the experiment would not have been a fair one. My tests where consistent, with one exception which was rectified when repeated. This suggests that my method had a dependable output. The use of a colorimeter provided consistency and accuracy over a visual colour check. I can conclude this because the line of best fit on the graph is predominantly smooth. However, I believe the reliability and precision of data has proved adequate to support my conclusion that as temperature increases, light transmission decreases. The limitations noted were minimal in regard to the resources available. Overall, I believe that they didn't greatly corrupt the expected trend. ?? ?? ?? ?? Will Garratt Biology coursework Miss. Brough ...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 Green Plants as Organisms 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

# Related GCSE Green Plants as Organisms essays

1. ## How does temperature affect the permeability of a cell membrane in a beetroot.

4 star(s)

10 minutes from when beetroot in heated test tube. Safety goggles To protect my eyes. Results table and pen To record my results. Cuvette To place the solution in to put in the colorimeter. Colorimeter / Blue filter To test the light % through the solution. In the colorimeter I would use a blue filter, as it is the closest to the pigment anthocyanin found in the beetroot.

2. ## Core practical - Why does the colour leak out of cooked beetroot? Investigating the ...

4 star(s)

The fluid in each of the test tubes will be analysed using a colorimeter and compared against the control, which is distilled water to check for any variations in the colour of the water. The colorimeter is now needed so must be set to read 0% absorbance with a green 550 filter.

1. ## Investigating to see what effect temperature has on the permeability of the beetroot cell ...

As the temperature increases the permeability of the membrane also increases allowing more pigment to leak out. Due to this reason more light is absorbed with increasing temperature when the solution is placed into the colorimeter. On the other hand there is one anomalous result which is for the 40�C temperature as this value does not follow the general trend.

2. ## The effect of temperature on membrane structure

Beetroot contains a pigment called betalain, found in the vacuole which gives the beetroot its characteristic purple colour. Betalain pigments are polar molecules and so are unable to pass through the phospholipid bilayer and can only pass through special channel proteins.

1. ## Poikilohydry in mosses: an ecological limitation or opportunity?

Chlorophyll-fluorescence measurements show that photosystem recovery after re-hydration is rapid9.The recovery of respiration after prolonged desiccation similarly shows recovery in mosses5. It has been suggested that recovery after desiccation involves the reestablishment of membrane integrity and photosystems10. At the scale of a moss gametophyte colony, surface tension is determines the distribution of water around the vegetative tissue5.

2. ## The factors affecting the rate of permeability in a cell membrane?

The diffusion of water through a partially permeable membrane down a water potential gradient is osmosis. Diagram : http://www.okc.cc.ok.us/biologylabs/Images/Cells_Membranes/osmosis.gif Diffusion Diffusion is the net movement of molecules from a place of higher concentration to a place of lower concentration. The molecules move down a concentration gradient.

1. ## The effect of temperature on membrane permeability

Caution when using knife. 2. Wash the strips of beetroot and place in distilled water. This is to ensure all the colour is washed out. As when cutting the beetroots which may cause the breakage of the cell walls. 3.

2. ## An Investigation into the effect of Temperature on the release of Betalain from Beetroot ...

of the solution by the time given for the diffusion to take place. % / Time = Rate of Diffusion This is assuming the pigment release is constant Equipment Details Colorimeter, device used to compare or measure colours and their intensities.

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