Tag Archives: plasma membrane

Effect of temperature on cell membranes using beetroot




Image source

In the egg osmosis experiment we used a chicken egg as a model of an animal cell to demonstrate the movement of water across a semi-permeable membrane. We have learned about the different components of the plasma membrane, including the phospholipid bilayer, integral and peripheral proteins, glycoproteins and glycolipids. We know that it is sometimes referred to as a “fluid mosaic” referring to it’s flexible structure of different parts.

Today we are going to test the effect of temperature and solvents on the cell membrane, using cores of raw beetroot. Beetroot is brightly coloured due to the presence of betalain and this coloured pigment can assist us to determine the effect of different temperatures and concentrations of solvents on the cell membrane. When the cell membrane is damaged, the pigment leaks out, so the more damage that occurs, the darker the colour of the medium into which the pigment leaks.

Your task is to design and complete an experiment with an aim, hypothesis, list of materials and equipment, method, results, discussion and conclusion. Your variable can be temperature OR concentration of a solvent (ethanol, for example) or detergent.


Effect of Temperature on Plasma Membranes

beetroot prac large

Test Tube D (added later than others), Test tube C, test tube B and test tube A

The prac was aimed to show us the effect of different environmental temperatures on a plant plasma membranes.

Test tube A contains a beetroot core placed in 70 degree celcius water,

Test tube B contains a beetroot core placed in a 50 degree celcius water,

Test tube C contains a beetroot core placed in  room temperature water,

and test tube D contains a beetroot core, frozen overnight and then placed in water.

We found that treatments to Test tube A and D had the most  effect on the beetroot core. This is because the temperatures ruptured membranes allowing the red pigments inside the beetroot core to escape! The hotter or colder the temperatures were, the more membranes burst and more colour was released. The colour is contianed in plastids within the cell membranes of the beetroot.

Brilliantly written by Year 11 VCE biology students,

Chloe Wood the fantastic and Emily Huglin the awesome!