Question

(a) A scientist investigates the effect of immersion of plant cells in different concentrations of sugar solution. Fig. 7.1 shows the appearance of the plant cells before immersion.

Beakers A–D contain different concentrations of sugar solution. Some plant cells are placed in each solution and left for an hour. Table 7.1 shows the results.

(i) Describe the change seen to the plant cells placed in beaker A in Table 7.1.

▶️Answer/Explanation

The cells swell or increase in size due to water entering the cells by osmosis.

(ii) Suggest which beaker contains the solution with the same concentration as the plant cells. Give a reason for your answer.

▶️Answer/Explanation

Beaker B; the cells have not changed, indicating that the concentration of the solution is the same as inside the cells, so there is no net movement of water.

(b) Water enters the plant through the root hair cells. Complete the flow chart to show the pathway of water through the cells of a plant.

root hair cell → …… → xylem → ……

▶️Answer/Explanation

root hair cell → root cortex cell → xylem → mesophyll cell

(c) Xylem transports water through the plant stem. Name the tissue that transports sugars through the plant stem.

▶️Answer/Explanation

Phloem

(d) Water and carbon dioxide are raw materials required for photosynthesis. Name two other requirements for photosynthesis.

▶️Answer/Explanation

1. Light
2. Chlorophyll

(e) Protecting land from deforestation helps stop the loss of soil. This is because tree roots hold the soil together, stopping it being washed away. Suggest two other benefits of protecting land from deforestation.

▶️Answer/Explanation

1. Prevents extinction of animals
2. Maintains biodiversity