Hypothesis:-
My hypothesis is that when temperature increases the proteins in the membrane will be denatured and the pigment will leak out of the cell membranes and will colour the water in the test tubes.
Method:-
Apparatus:- a thin cylinder of beetroot tissues, nine test tubes, beaker ,Bunsen burner, water, thermometer, colorimeter.
Variables:-
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Independent: Time, temperature
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Dependant: Intensity of red in water
Procedure
- We were provided with thin cylinders of beetroot tissue, which was washed in running water overnight.
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We took nine test tubes and labelled them from A-I. And we placed 6 cm3 of water in each tube with the help of pipette.
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We put nine cylinders of beet root tissues into a beaker of 150 cm3 of water.
- We put a beaker on a Bunsen burner and took some water and heated the water and then put a thermometer in to the beaker.
- We put beet root in to the hot water for two minutes and noted the temperature.
- We transferred the beetroot to the test tube A and allowed it for 20 minutes.
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We reduced the temperature of the water by75°C by using cold water. This method was used by reducing temperature the water to 65°C, 55°C, 45°C, 30°C, and 25°C.
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Put beetroot in to the crushed ice at 15°C and allow for 20 minutes.
- We measured the intensity of red in the water by using colorimeter. We filled another curette with distilled water as a control to get 100% transmission.
Safety:-_
- Hot water: heating water on a Bunsen burner means great care mast be taken to avoid scalding.
- Knife: when using a knife care must be taken because you might damage your self.
- Do not eat beetroot because it is not clean and it is old.
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- Bunsen burner: care must be taken other wise it you may burn your hand.
Result:-
Conclusion:-
My hypothesis was proven as the temperature increased the leakage of beetroot cell membrane started leaking, the proteins in the membrane denatured and the pigment leaked out of the cell membranes and coloured the water red in the test tubes. However it did not start leaking from the 15°C and it started leaking from 30°C.
Evaluation:-
If I get a chance to do the experiment again I would try to improve it. There are several ways I could do this. Colour intensities could be measured more accurately by means of a more accurate colorimeter accurately. Alternatively, a semi-quantitative method may be used: for example take 1 ml solution from the most intensely coloured tube as a colour control which can matched by pouring the next less intense solution into a second tube and adjusting the volume until the colour of the two tubes match one another when viewed from the top. The height of the solution in the second typeis
an indication of the relative light intensity of the solution. It is possible that physical damage done to the beetroot cells when handling them, during the transfer from one
tube to another could have affected the outcome. Some more careful handling of the beetroot would be essential.
Reference:- Salters-Nuffield Advanced biology. (2005)
