Required Practical 3: Effects of Osmosis on Plant Tissue

• What is osmosis?

  Diffusion of water through a membrane
• What happens to plant cells when placed in water?

  Water moves in, causing cells to expand
• What occurs when plant cells are placed in a concentrated solution?

  Water moves out, causing cells to shrink
• What type of vegetable is commonly used to investigate osmosis?

  Potato
• Why do we peel the potato before the experiment?

  The skin can affect osmosis
• What tool is used to produce potato cylinders?

  Cork board
• Why is it important to make all potato cylinders the same diameter?

  To ensure consistent osmosis results
• What is the ideal length for potato cylinders?

  About three centimeters
• What should you measure for each potato cylinder before the experiment?

  Length and mass
• What volume of 0.5 molar sugar solution is added to the first test tube?

  10 centimeters cubed
• Why do we use distilled water instead of tap water?

  Distilled water has no dissolved substances
• What should you do after leaving the potato cylinders overnight?

  Gently roll them on paper towel
• Why is it important not to press on the potato cylinders?

  To avoid forcing water out of cells
• What is the formula for percentage change?

  Percentage change = (change/original) × 100
• What does the graph of percentage changes in mass or length show?

  Mass changes with sugar solution concentration
• What does it mean when the graph crosses the x-axis?

  No change in mass occurs
• What does the concentration at the x-axis crossing indicate?

  Approximate concentration inside the cell