required practical: effects of osmosis on plant tissue

• What is osmosis?

  Diffusion of water through a membrane
• What happens to plant cells 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 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 borer
• What length should the potato cylinders be trimmed to?

  Approximately three centimeters
• Why is it important to use cylinders of the same diameter?

  To ensure consistent surface area for osmosis
• What should be measured before placing the potato cylinders in the solution?

  Length and mass of each cylinder
• 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 contains no dissolved substances
• What should be done to the potato cylinders after soaking overnight?

  Gently roll them on paper towel
• What is the formula to calculate percentage change?

  Percentage change = (change/original) × 100
• If a potato cylinder has a starting mass of 1.56 grams and increases by 0.25 grams, what is the percentage change?

  +16.03 percent
• If a potato cylinder has a starting mass of 1.32 grams and decreases by 0.19 grams, what is the percentage change?

  • 14.39 percent
• What does the graph of percentage changes in mass or length against sugar concentration show?

  Mass changes with varying sugar concentrations
• 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
• What are the steps to investigate the effect of osmosis on plant tissue?

  1. Peel the potato.
  2. Use a cork borer to create cylinders.
  3. Trim cylinders to the same length.
  4. Measure length and mass of cylinders.
  5. Place cylinders in different sugar solutions.
  6. Leave overnight for osmosis.
  7. Roll on paper towel to remove moisture.
  8. Measure length and mass again.
  9. Calculate percentage change.
• What are the types of solutions used in the osmosis experiment?

  • 0.5 molar sugar solution
  • 1.25 molar sugar solution
  • Distilled water
• What are the key concepts related to osmosis in plant cells?

  • Water moves from dilute to concentrated solutions.
  • Plant cells expand in dilute solutions.
  • Plant cells shrink in concentrated solutions.