Formative Practice 3.3 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
Explain what will happen to the following cells when they are soaked in a solution with a higher concentration of solutes compared to the intracellular fluid:
(a) red blood cells
(b) plant cells

(a) Red blood cells undergo crenation.

(b) Plant cells undergo plasmolysis.

Question 2:
Explain the effect of the hypotonic solution on red blood cells.

When red blood cells are put into a hypotonic solution, water is absorbed into the cell via osmosis, causing the cell to expand and eventually burst.
The rupture of red blood cells is known as haemolysis.

Question 3:
Explain the effect of the isotonic solution on plant cells.

When the plant cell sap and its external solution are isotonic, the values of the water potential are the same. Water movement in and out of the cell is the same. The cell becomes flaccid.

Question 4:
Explain the following situations based on the osmosis concept:
(a) Why do hawkers spray water on their fruits and vegetables?
(b) Explain what happens when sugar is sprinkled on strawberries.

Water diffuses into vegetable cells and fruit cells via osmosis causing the vacuole to expand. Cell sap within the vacuole pushes the cytoplasm and plasma membrane towards the cell wall, causing the vegetable cells and fruit cells to become turgid again.

The external environment becomes hypertonic compared to the cell sap within the strawberry cells. This causes water to diffuse out of the strawberry via osmosis.

Leave a Comment