Question 1: Define osmosis in your own words.

Answer: Osmosis is the movement of water molecules across a semi-permeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Question 2: Explain how osmosis differs from diffusion.

Answer: Osmosis specifically involves water movement across a semi-permeable membrane, whereas diffusion can involve any molecules moving from high to low concentration without the need for a membrane.

Question 3: Describe what happens to a plant cell placed in a hypertonic solution.

Answer: The plant cell will lose water, causing the cytoplasm to shrink and the cell membrane to pull away from the cell wall, leading to plasmolysis.

Question 4: Identify the key factor that determines the direction of water movement during osmosis.

Answer: The concentration gradient of solutes across the semi-permeable membrane.

Question 5: In an experiment, a semi-permeable membrane separates two solutions. Solution A has 0.2 mol/L of salt, and Solution B has 0.5 mol/L. Which way will water move?

Answer: From Solution A to Solution B

Question 6: Fill in the blank: During osmosis, water moves from an area of ______ solute concentration to an area of ______ solute concentration.

Answer: lower, higher

Question 7: Calculate the net water movement if a cell is placed in a solution with a solute concentration of 0.3 mol/L, while the cell's internal concentration is 0.6 mol/L. Assume the movement is from the area of lower to higher concentration. Show your working.

Answer: Since water moves from lower to higher solute concentration, the net movement is from the external solution to the cell's interior. No numerical answer is required, but students should explain the direction based on the concentration difference.

Question 8: Describe a practical experiment to demonstrate osmosis in potato cells, including variables to control and safety precautions.

Answer: Students cut potato samples and place them in solutions of varying salt concentrations. Variables to control include temperature, potato size, and solution volume. Safety precautions involve handling sharp knives carefully and wearing safety goggles. The experiment demonstrates osmosis by observing changes in potato tissue weight or firmness.

Question 9: Interpret the following scenario: A human red blood cell is placed in pure water. Explain what happens to the cell and why.

Answer: The red blood cell will swell and potentially burst (hemolysis) because water enters the cell via osmosis, moving from the area of lower solute concentration outside the cell to the higher solute concentration inside.

Question 10: Apply your understanding of osmosis to explain how water balance is maintained in desert plants.

Answer: Desert plants have adaptations such as thick cuticles, sunken stomata, and succulent tissues to reduce water loss and manage water uptake, relying on osmotic regulation to maintain water balance in arid conditions.