Cells: Investigating Cell Membrane Permeability Practical

Question 1

What is the aim of this practical?

Answer 1

• The aim is to investigate how different variables (e.g temperature and solvent concentration) affect cell membrane permeability by doing experiments using beetroot
• Beetroot cells contain a coloured pigment that leaks out - the higher the permeability of the membrane, the more pigment leaks out of the cell

Question 2

Describe how to carry out this practical

Answer 2

• Use a scalpel to cut five equal sized pieces of beetroot. Rinse the pieces to remove any pigment released during cuttinf
• Add five pieces to five different test tubes, each containing 5cm3 of water
• Place each test tube in a water bath at a different temperature, for the same length of time
• Remove pieces of beetroot from tubes, leaving the coloured liquid
• Switch a colorimeter on and use blue filter
• Add distilled water to a cuvette and put in colorimter and calibrate machine to zero
• Transfer sample of liquid from first test tube to a clean cuvette
• Place in colorimter and record absorbance of solution
• Repeat with other solutions
• Analyse results - the higher the absorbance reading, the more pigment released, so the higher the permeability of membrane