Beetroot Practical

Question 1

Describe and explain the effect temperature has on membrane permeability

Answer 1

Increasing the temp increases the kinetic energy of the components within the cell membrane. This causes them to move around more creating more gaps in the membrane and therefore increasing permeability.

Temperatures above 40 denature proteins on the membrane again creating more gaps

Question 2

Describe and explain the effect alcohol concentration has on membrane permeability

Answer 2

As it’s non polar, it causes the phospholipids to rearrange themselves disrupting the membrane increasing permeability

Question 3

Devise a method to investigate the effect temperature has on membrane permeability

Answer 3

• Produce a ethanol solution with a specific concentration (20cm ).
• Prepare 1cm3 samples of beetroot. Leave in distilled water overnight.
• Place 5cm3 ethanol solution into 3 test tubes.
• Place 1cm3 of beetroot in each test tube.
• Leave for 30 minutes.
• Calibrate colorimeter (2cm3 of distilled water) at 0 abs (Press R).
• Measure absorbency of each solution (2cm3) (Press T) and calculate average

Question 4

Devise a method to investigate the effect alcohol concentration has on membrane permeability

Answer 4

1. 1cm3 cubes of beetroot – rinse and leave in DI water overnight
2. 5cm3 of distilled water in test tubes in water baths to acclimatise (5 mins) - 100C, 200C, 300C 400C, 500C 600C, 700C
3. Place cubes in water in test tubes – leave for 60 mins
4. Colorimeter – blue/green filter (490nm), distilled water in cuvette – 0 au absorbency
5. Measure absorbency (au) for each beetroot solution Calculate average absorbency (au) for each temperature