RP04 - Investigating cell membrane permeability

Question 1

State two factors that effect the permeability of cell membrane

Answer 1

• Temperature
• Concentrations of solvents (ethanol)

Question 2

How is beetroot used to measure the permeability of cell membrane?

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 pigments

Question 3

Outline the procedure to investigate the effect of temperature on permeability of cell membranes

Answer 3

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

Question 4

What are the safety hazards

Answer 4

• Ethanol is an irritant and flammable keep away from naked flame and wear eye protection
• Keep sharp scalpel away from fingers
• Handle hot liquid with care

Question 5

What is the effect on temperature on membrane permeability?

Answer 5

Increasing temperature results in increase membrane permeability

Question 6

What is the effect of ethanol concentration on membrane permeability?

Answer 6

Increasing ethanol concentrations leads to increased membrane permeability