Question

The diagram below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:

(i) What is the state of the cell shown in the diagram?

(ii) Name the structure that acts as a selectively permeable membrane.

(iii) Write the difference between the cell wall and plasma membrane.

(iv) How can the above cell be brought back to its original condition?

(v) Write one difference between diffusion and osmosis.

Answer 1

(i) State of the cell shown in the diagram

1. In the diagram, a plant cell is placed in a strong sugar solution. The sugar solution is a hypertonic solution. When the external solution is more concentrated than the cell cytoplasm, it is referred to as a hypertonic solution.
2. When a plant cell is placed in a hypertonic solution, the water moves out of the cell, and the cell membrane shrinks away from the cell wall. This process is known as plasmolysis. The cell shown in the diagram is in the plasmolyzed state.

(ii) The structure that acts as a selectively permeable membrane is called the cell or plasma membrane.

(iii) Difference between the cell wall and plasma membrane

(iv) The plasmolyzed cell shown in the diagram can be brought back to its original condition by a process called deplasmolysis. It involves placing the plant cell in a hypotonic solution (solution with fewer solutes) which allows diffusion of water into the cell.

(v) Difference between diffusion and osmosis

Diffusion	Osmosis
Diffusion is defined as the movement of molecules from a region of their higher concentration to a region of their lower concentration. It occurs in liquid, gas, and solid medium.	Osmosis refers to the movement of solvent molecules across a semipermeable membrane from a region of higher concentration to a region of lower concentration until equilibrium is reached. It occurs only in a liquid medium.