Question

Given below is the diagram of an apparatus setup to study a very important physiological process:

(i) Name the process being studied.

(ii) Explain the process.

(iii) What change would you observe in the thistle funnel containing sugar solution after about 10 minutes?

(iv) Is sugar solution hypertonic or hypotonic?

(v) Name the part of the plant cell which is represented by the sugar solution.

Answer 1

(i) Name of the process studied here:

1. Take a long-stemmed inverted thistle funnel and tie its mouth with a piece of animal bladder or parchment paper.
2. Pour 10% sugar solution into the thistle funnel slowly till it reaches one-third of the height of the stem and dips the mouth end of the funnel in a beaker having pure water.
3. Fix the stem of the thistle funnel in a vertical position using a stand. Mark the level of the solution as ‘A’.
4. After some time, a rise in the level of solution in the stem of the thistle funnel will be noticed.
5. The level of water in the beaker decreases slightly.
6. In the beaker, the water does not taste sweet.
7. The rise of the level of solution in the thistle funnel can occur only if water passes into it from the beaker.
8. This process is called osmosis.

(ii) Osmosis:

1. Osmosis is the diffusion of water across a semipermeable membrane from the region of its higher concentration to the region of its lower concentration.
2. A high concentration of water occurs in pure water or a comparatively dilute solution.
3. The semipermeable membrane has minute pores which do not allow passage of solute particles but are permeable to water molecules as per their concentration.
4. As a result, more water will pass from the side of pure water or dilute solution to the side where its amount is low due to the presence of more solute particles.
5. The volume of the solution will, therefore, increase.

(iii) Observation of changes in experimental setup:

After 10 minutes, the sugar solution level in the thistle funnel will start to rise up.

(iv) Hypertonic solution:

1. The sugar solution is a hypertonic solution.
2. Hypertonic solution: It is a concentrated solution that has an osmotic concentration higher than that of another solution.

(v) Cell sap:

1. Cell sap is the fluid found in the cellular vacuoles of a cell.
2. Cell sap contains food materials and waste materials, inorganic salts, and nitrogenous compounds.
3. So, the cell sap is the part of the plant cell which is represented by the sugar solution.