RP04: Investigating Cell Membrane Permeability

Question 1

State 2 factors that affect permeability of cell membranes

Answer 1

Temp

Conc of solvents (ethanol)

Question 2

How is beetroot used to measure permeability of cell membranes

Answer 2

The higher the permeability, the more red pigment that leaks out into the surrounding solution within a given time. A colorimeter can be used to determine the absorbance, hence concentration of pigment.

Question 3

Outline procedure to investigate effect of temp on permeability of cell membrane

Answer 3

1. Cut beetroot into 6 identical cubes with a scalpel.
2. Place each cube in a different test tube with equal volumes of distilled water.
3. Place each test tube into water baths ranging from 30-80°C. Leave for 20 minutes.
4. Filter each solution out into a cuvette and measure the absorbance using a colorimeter.

Question 4

What are safety hazards involved in testing effect of ethanol conc on membrane permeability

Answer 4

Ethanol is an irritant and is flammable, keep away from naked flames, wear eye protection

Keep sharp scalpel away from fingers

Handle hot liquid with care

Question 5

What is effect of temp on membrane permeability

Answer 5

Increasing temp results in increase in membrane permeability

Question 6

What is effect of ethanol conc on membrane permeability

Answer 6

Increasing ethanol conc leads to increased membrane permeability