4 - Investigating cell membrane permeability

Question 1

Give 2 control variables

Answer 1

• volume of distilled water in each test tube so the same volume of water is able to pass through the membrane
• side of the beetroot chips so the SA is same

Question 2

Suggest why the water in the test tubes were placed in the water bath for 5 mins before beetroot chips were added

Answer 2

So the temp of water can reach the temp at which the reaction should take place

Question 3

Why were the beetroot chips washed with distilled water and dried before the experiment began?

Answer 3

To remove excess surface pigment from the cut cells at the edge. This excess pigment would distort the transmission reading giving inaccurate results

Question 4

Describe what happens to the beetroot cell membranes if the temperature rises above biological temperatures

Answer 4

Increase in temp causes an increase in kinetic energy. When temp rises above biological temperatures the proteins denature making membrane more permeable cause gale to open and further increases cause membrane to be destroyed