investigation into the effect of alcohol on the permeability of cell surface membranes (beetroot cells)- 4

Question 1

investigation into the effect of alcohol on the permeability of cell surface membranes (beetroot cells)

Question 2

Describe the method used?

Answer 2

1. set up 6 McCartney bottles, using a measuring cylinder add 5 ml of each concentration from 80- 0% alcohol concentration
2. label each bottle with the corresponding alcohol concentration
3. cut 1cm block og beetroot (12 pieces) and wash them under running water. Blot each of them dry with a paper towel
4. Gently put two blocks of beetroot in each of the five test tubes. place the lid on the bottles as soon as you place the beetroot in.
5. shakes tubes gently every minute for 5 minutes.
6. remove the beetroot discs away
7. and pour the liquid into the cuvette.
8. set up your colorimeter, zero the colorimeter with a cuvette of water. then measure the absorbance of each sample, making sure you zero the colorimeter between the readings.
9. record your results in a table

Question 3

what does beetroot contain?

Answer 3

high concentrations of betalin. this is a purple pigment found inside the vacuoles of the cells.

Question 4

How can this pigment be used for this experiment?

Answer 4

the pigment can not move across cell membranes

Question 5

why as the beetroot discs washed before the experiment started?

Answer 5

to wash away any excess pigment that may have been released from cutting, and would stain the water before experiments starts

Question 6

why do we have the shake the botte after each minute has passed?

Answer 6

to prevent pigment of sticking to the surface of the glass in the McCartney bottles

Question 7

why did we have to immediately pour the alcohol immediately from the experimental test tube from the experimental test tube into a clean test tube?

Answer 7

we have to control the amount of time the beetroot sits in he alcohol, so it’s a fair test and comparisons can be made

Question 8

why would results be different if we had used cooked beetroot?

Answer 8

the pigment would have been already absorbed/ dryed up so no pigment would have been released

Question 9

why would a decrease in temperature affect the results?

Answer 9

pigment will be released more slowly as there is less pressure on pushing the pigment out of the plasma membrane