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

Beetroot experiment

Extracts from this document...

Introduction

Nanye Osae-Asare BEETROOT REPORT PLAN The aim of the following experiment is to use beetroot to examine the effect of temperature on cell membranes and relate the effects observed membrane structure. Hypothesis I predict that upon heating beetroot to a certain temperature colour will leak out and give out a reading on a colorimeter. Scientific Background Beetroot is a vegetable which is used greatly in food making and an important ingredient in recipe books. It is usually recommended that you don't remove the outer skin of the beetroot and don't cut off all the stalk and root if you want to avoid getting lots of red dye in the cooking water. Beetroot contains red pigments called betalains, located within the cell vacuole. Normally the pigments cannot pass through membranes but they leak out when the beetroot is cooked or put in alcohol. The beetroot is protected by a cell membrane. The cell membrane functions as a semi-permeable barrier, allowing a very few molecules across it while fencing the majority of organically produced chemicals inside the cell. Electron microscopic examinations of cell membranes have led to the development of the lipid bilayer model (also referred to as the fluid-mosaic model). The most common molecule in the model is the phospholipids, which has a polar (hydrophilic) ...read more.

Middle

2 boiling tube racks 9. Crushed ice 10. 8 Boiling tubes 11. Thermometer(one per water bath) 12. Colorimeter to measure amount of colouration produced. 13. Cuvettes 14. Stop clock 15. Distilled water 16. Pipettes for measuring 2cm3 and 5cm3 17. Small measuring cylinders. Procedure 1. Cut sections from a single beetroot using a size 4 cork borer. Cut eight, 1cm length slices from these sections. Be careful not to spill beetroot juice on skin or clothing since it stains very badly. 2. Place the slices in a beaker of distilled water. Leave overnight to wash away excess dye. 3. Next day, place eight labelled boiling tubes each containing 5cm3 distilled water into water baths at 0oC, 10oC, 20oC, 30oC, 40oC, 50oC, 60oC and 70oC. Leave for 5 minutes until the water reaches the required temperature. Place one of the beetroot sections into each of the boiling tubes. Leave for 30minutes in the water baths. 4. Decant the liquid into a second boiling tube and remove beetroot sections using a technique that does not squeeze the slice e.g. spear with a pointed seeker. Shake the water/solution to disperse the dye. 5. Switch on the colorimeter and set it to read % absorbance. 6. Set the filter dial to the blue/green filter. ...read more.

Conclusion

Colorimeter reading was lowest at 0oC 4. There was a significant rise in colorimeter reading from that at 50oC and 60oC. Explanation for results 1. Colorimeter reading stood for the amounts of betalain solution that passed through the cell membrane of the beetroot. As temperature increased, so did the size of pores in the membrane which allowed more and more betalain to escape from the cell. This supports the fact that temperature and colorimeter reading was directly proportional. 2. At 70oC the pores in the beetroot's were open the widest allowing the most betalian solution to leave the vacuole through the cell membrane. This explained why the colorimeter reading was highest for the beetroot tat was heated in the 70oC water bath. 3. At 0oC, the low temperature causes the pores to constrict and less amount of betalian solution is allowed to pass through the cell membrane. Since less amount of betalain is allowed to pass through, this means that colorimeter reading will be low. The results show that this was indeed the case. 4. From 0oC to 40oC, the molecules of the betalin solution possess relatively the same amount of energy. From 50oC betalin molecules have acquired a greater amount of energy and are free to move. This combines with the effect of temperature on the cell membrane pores to allow a greater than usual amount of betalin solution to leave to cell via the cell membrane. Evaluation 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

Here's what a teacher thought of this essay

3 star(s)

Overall, this report of an investigation into the effect of temperature on the permeability of biological membranes is well-structured with a fair degree of supporting theory. Most of the key areas are covered in a logical order allowing the reader to follow the scientific process. There are, however, a number of weaknesses that would need to be addressed before submitting this as A'Level coursework. [1] The hypothesis needs to refer to the relationship between IV and DV; [2] The introduction needs to be wholly focused on the area of biology under investigation - membrane structure and effect of heat on permeability; [3] Control variables need to be discussed in full with the aim of increasing the validity of the results; [4] The results themselves need to be discussed in the light of sound biological facts with references to previous work by other biologists on the same hypothesis.

Marked by teacher Ross Robertson 15/04/2013

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. To investigate how temperature affects the concentration of vitamin C in orange juice (specifically ...

    Therefore while the first few vitamin C molecules don't require a large amount of heat energy to break down, the last few, with a small surface area and low concentration, would take a huge amount of heat energy to break down which we did not provide.

  2. A2 coursework- The effects of bile salts on digestion of fat

    on the outside of the molecule ensuring that they are soluble".9 So lipase is a soluble molecule, however fat is not and so this is what makes it difficult for the lipase to act on the fat but it is bile salts that aid this reaction to allow fat digestion to occur.

  1. To find out how different concentrations of sucrose solution affect the incipient plasmolysis of ...

    Finally leave all the root vegetable cylinders in the McCartney bottles over night, they all must be kept for the same time period.

  2. The Effect of Soaking on the Action of Catalase.

    > 50cm� Measuring Cylinder - this is more accurate to use to measure the volume of oxygen produced rather than counting the amount of bubbles as they vary in size and are occasionally released too fast. > 15cm� Beaker-for the hydrogen peroxide > 500cm� Beaker-for the water bath > Thermometer

  1. Why does the colour leak out of cooked beetroot?

    Beetroot left in water for wrong time Time each sample carefully with a stopwatch If the beetroot is left in too long, more dye will diffuse out If the beetroot is left in too long, the % absorbance will be greater Systematic if all are left in for too long

  2. Why does the colour leak out of cooked beetroot?

    control as well as doing the following things: ?I will leave the boiling tubes of water in the water baths for 5 minutes before I add the beetroot pieces to them, so that they have reached the required temperatures. ?I will leave the boiling tubes containing water and beetroot in

  1. Investigating Osmosis.

    only variable that we are altering is the concentration of the solution. Although ideally the experiment would be repeated several times, we were not able to do this as we did not have sufficient time. After 24 hours we remove the cylinders from solution and, with callipers, which are more

  2. Experiment 3 : Identification Of Food Constituents In Milk

    The change in colour of Benedict?s test is determined by the amount of reducing sugar present and the colour change will progress from green, yellow, orange, red and then a dark red or brown. The results suggest that milk K2 has higher concentration of reducing sugar compare to milk K1.

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