Practical 4

Question 1

state 2 factors that affect the permeability of cell membranes

Answer 1

temperature
concentration of solvents

Question 2

how is beetroot used to measure the permeability of cell membranes

Answer 2

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

Question 3

outline the procedure to investigate the effect of temperature on permeability of cell membrane

Answer 3

1. cut each beetroot into 6 identical cubes with a scalpel
2. place each cube in different test tube wit equal volumes of distilled water
3. place each test tube into water baths ranging from 30 to 80c an clean for 20 minutes
4. filter each solution out into cuvette and measure the absorbance using colorimeter

Question 4

what are the safety hazards involved in testing the effect of ethanol concentration on membrane permeability

Answer 4

ethanol is irritant ad flammable
keep scalpel away from fingers
handle hot liquid with care

Question 5

what is the effect of temperature on membrane permeability

Answer 5

increasing temperature increases membrane permeability

Question 6

what is the effect of ethanol concentration on membrane permeability

Answer 6

increasing ethanol concentration leads to increased membrane permeability