Question

Write an activity to show that selective permeability exists in a living plasma membrane only

Answer 1

Dear student,

An activity could be done using Rheo leaf.

Materials required: Rheo leaf, slides, coverslip,sugar solution,microscope.

Procedure 1 : 1. Take a peel of Rheo leaf and mount it on a slide.
2. Put a drop of strong sugar solution on the mounted peel and cover with a coverslip.
3. Observe it under microscope after few minutes.
4.Cell membrane shrinks after few minutes.

This is because the outer medium is hypertonic. It leads to outflow of water from inside to outside of cells and hence plasmolysis occurs and the leaf cells shrinks.

Procedure 2 : 1.Take peel of Rheo leaf and place it in boiled water for few minutes.
2. Repeat the steps as in Procedure1

​Here, no plasmolysis is observed because the cell membranes are damaged due to high temperature . Thus,no osmotic activity is shown in this case.

Thus, this activity shows selective permeability exists in a living plasma membrane only.

Regards.