Which diagram shows the result of the experiment after 24 hours?

Here are the solutions to the questions:

Question 6:

• Which diagram shows the result of the experiment after 24 hours?

  • Step 1: Understand the principle of osmosis. Osmosis is the net movement of water molecules from a region of higher water potential to a region of lower water potential across a partially permeable membrane.
  • Step 2: Analyze the setup. The potato cavity contains a concentrated sugar solution, which has a lower water potential. The beaker contains water, which has a higher water potential. The potato cells act as a partially permeable membrane.
  • Step 3: Predict the movement of water. Water will move by osmosis from the beaker (higher water potential) through the potato cells into the concentrated sugar solution in the cavity (lower water potential). This will cause the volume of liquid in the cavity to increase and the water level in the beaker to decrease.
  • Step 4: Compare with the diagrams. Diagram B shows the water level in the potato cavity rising and the water level in the beaker dropping, which matches the prediction.

  The correct option is B.

Question 7:

• A learner draws a biological diagram of a plant cell. The diameter of the diagram is $40 \text{ mm}$. The plant cell has a diameter of $0.02 \text{ mm}$. What is the magnification of the learner's drawing?

  • Step 1: State the formula for magnification. The magnification is calculated using the formula: $$\text{Magnification} = \frac{\text{Image size}}{\text{Actual size}}$$
  • Step 2: Substitute the given values into the formula. Image size (diameter of diagram) $= 40 \text{ mm}$ Actual size (diameter of plant cell) $= 0.02 \text{ mm}$ $$\text{Magnification} = \frac{40 \text{ mm}}{0.02 \text{ mm}}$$
  • Step 3: Calculate the magnification. $$\text{Magnification} = \frac{40}{0.02} = \frac{40}{\frac{2}{100}} = 40 \times \frac{100}{2} = 20 \times 100 = 2000$$
  • Step 4: State the final answer. The magnification is $\boxed{\text{x 2000}}$.

  The correct option is D.

Question 8:

• How does water vapour move through the stomata of a leaf on a dry, sunny day?

  • Step 1: Understand the conditions. On a dry, sunny day, the air outside the leaf has a lower concentration of water vapour (lower water potential) compared to the air spaces inside the leaf, which are saturated with water vapour.
  • Step 2: Identify the process of movement. Water vapour moves from a region of higher concentration (inside the leaf) to a region of lower concentration (outside the leaf) through the stomata. This movement is called diffusion.
  • Step 3: Determine the direction of movement. Due to the concentration gradient, water vapour moves out of the leaf.

  The correct option is C) out of the leaf by diffusion.