permeability

Question 1

what factors affect membrane permeability

Answer 1

-temperature
-solvent concentration

Question 2

explain how solvent concentration can affect membrane permeability

Answer 2

surrounding cells in a solvent can increase permeability if it is able to dissolve the lipids in the cell membrane causing it to loose its structure

Question 3

how can temperature affect membrane permeability?

Answer 3

as temperature increases the phospholipid bilayer starts to melt as they have more kinetic energy = not as packed closely = more permeable

Question 4

explain how the beetroot practical shows membrane permeability

Answer 4

beetroot cells contain a coloured pigment that leaks out - the higher the temp of water = higher permeability = more pigment leaks out

Question 5

what are some limitations of the beetroot practical?

what are the solutions

Answer 5

-some parts of the beetroot tissues have more pigment in their cells than others = conduct several repeats using different parts of beetroot and find mean

-beetroot pieces may not all be identical size = cut discs as accurately as possible using a scalpel and ruler and repeat investigation finding mean

Question 6

what is repeatability?

what is reproducibility

Answer 6

-ability to get the same results when repeating the same experiment under the same conditions

-ability to get the same results when repeating the same experiment under different conditions

Question 7

what is accuracy?

what is precision

what is validity-

Answer 7

-how close each result is to the true value

-the ability to be exact

-how well the experiment measures what it is intended to measure

Question 8

what are limitations

what are sources of error

Answer 8

-factors that are out of your control

-factors that reduce the accuracy due to the method or equipment