osmosis + RP

• What should you be able to describe by the end of the video?

  Investigate the effect 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 into the cell, causing expansion
• What occurs when a plant cell is placed in a concentrated solution?

  Water moves out, causing the cell 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 uniform potato cylinders?

  Cork borer
• What is the ideal length for potato cylinders in the experiment?

  About three centimeters
• Why is it important to measure the length and mass of each cylinder?

  To assess the effect of osmosis accurately
• How much of a 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 be done after leaving the potato cylinders overnight?

  Gently roll them on paper towel
• What is the purpose of rolling the potato cylinders on paper towel?

  To remove surface moisture without pressing
• What equation is used to calculate percentage change?

  Percentage change = (change in value / original value) × 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 water movement by osmosis
• What does it mean when the graph crosses the x-axis?

  No change in mass occurs at that concentration
• 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 to occur.
  7. Roll cylinders on paper towel.
  8. Measure length and mass again.
  9. Calculate percentage change.
• What is osmosis?

  Diffusion of water through a membrane
• What does osmosis involve in terms of solutions?

  Water moves from dilute to concentrated solutions
• What are the key factors affecting osmosis in this experiment?

  • Concentration of sugar solution
  • Duration of immersion
  • Size and surface area of potato cylinders
  • Temperature of the environment
• What type of membrane does osmosis occur through?

  Partially permeable membrane
• What are the implications of osmosis for plant health?

  • Turgidity affects structural integrity.
  • Water loss leads to wilting.
  • Proper osmotic balance is crucial for nutrient uptake.
• What is a dilute sugar solution characterized by?

  High concentration of water molecules
• What is a concentrated sugar solution characterized by?

  Low concentration of water molecules
• What happens to water molecules in osmosis?

  They diffuse from high to low concentration
• What is the effect of osmosis on animal cells placed in water?

  The cell expands and may burst
• What happens to an animal cell in a concentrated solution?

  The cell shrinks as water moves out
• What is the effect of osmosis on plant cells placed in water?

  The cell becomes turgid and expands
• What prevents plant cells from bursting when they become turgid?

  The cell wall provides structural support
• What happens to a plant cell in a concentrated solution?

  The cell becomes flaccid as water moves out
• What are the effects of osmosis on animal and plant cells?

  • Animal cells in water: expand and may burst
  • Animal cells in concentrated solution: shrink
  • Plant cells in water: become turgid and expand
  • Plant cells in concentrated solution: become flaccid
• Why do you need to remove surface moisture using a paper towel

  So that excess water doesn’t contribute to the mass of the cylinders
• explain why the masses of both samples of cylinders increased

  • water moved into the cubes by osmosis
  • because the concentration of water was higher outside the cubes than inside the cells
• why is it better to calculate % change in mass rather than change in mass

  because the samples of cubes were different masses at the start of the investigation