Biology practical = investigating cell membranes

Question 1

Aim of this experiment

Answer 1

Effect of a named variable eg temperature or concentration of solution (concentration gradient) on the permeability of a membrane

Question 2

Overall outline

Answer 2

Produce test tubes of different temperatures in a water bath eg range from freezing to 80°c
Prepare beetroot chips of same surface area + rinse and blot dry
Place 1 in each tube and use colourimeter to measure how much pigment leaked out dependent on light absorption

Question 3

Findings of this experiment

Answer 3

As temp increases, gradual increase in colour intensity thus pigment leaked out due to increased kinetic energy of phospholipid molecules
Rapid increase when membrane proteins begin to denature

Question 4

Alternative factors to investigate

Answer 4

Concentrations of ethanol, the more concentrated the more phospholipids in the membrane are dissolved thus leaky the membrane is
pH, the further away from optimum, the membrane proteins will denature causing membrane to break down