Osmosis

• Osmosis

  The movement of water from a dilute solution to a more concentrated solution through a selectively permeable membrane
• selectively permeable membrane

  allows small molecules through (water) but not larger molecules (sugar)
• dilute solution

  • high water concentration
  • low sugar solution concentration
• (more) concentrated solution

  • low water concentration
  • high sugar solution concentration
  • lots of sugar molecules = less room for water
• two things required for osmosis

  1. two different concentrations of solutions (or water and a solution)
  2. departed by a selectively permeable membrane
• *Visking tubing containing sugar solution inside a beaker of water*

  describe and explain what happens after 24 hours

  • There are MORE water molecules OUTSIDE than inside the tubing
  • Water would move INTO the tubing and the tubing would EXPAND.
  • The visking tubing is selectively permeable.
• What is osmosis?

  Movement of water through a semipermeable membrane
• How does osmosis occur in plant cells?

  Water enters the cell through a selectively permeable membrane
• What happens to a plant cell during osmosis?

  The vacuole expands, pushing the membrane against the wall
• What is the role of the cell wall during osmosis in plant cells?

  The cell wall limits the expansion of the membrane
• What is turgor pressure in plant cells?

  Pressure from the vacuole against the cell wall
• What limits water intake in plant cells?

  The cell wall stops excessive membrane expansion
• What happens if a plant cell is surrounded by a more concentrated solution?

  The cell loses water through osmosis
• What is plasmolysis in plant cells?

  When a plant cell loses water and shrinks
• Why do plants need water?

  For support and transpiration processes
• What is the role of water in transpiration?

  Water moves up through the plant and evaporates
• How does water transport minerals in plants?

  Water carries minerals as it moves through the plant
• What is the significance of osmosis in plant cells?

  It maintains cell turgor and nutrient transport
• What is the state of a plant cell when it has gained enough water by osmosis?

  The cell is firm and turgid
• How does osmosis affect the firmness of a plant cell?

  Osmosis increases turgor pressure, making it firm
• What are the main functions of water in plants?

  • Provides support through turgor pressure
  • Facilitates nutrient transport
  • Aids in photosynthesis
  • Enables transpiration
• What are the consequences of plasmolysis in plant cells?

  • Cell shrinks away from the cell wall
  • Loss of turgor pressure
  • Reduced support for the plant
  • Potential wilting and death of the plant
• What is the process of osmosis in plant cells?

  1. Water enters the cell through osmosis
  2. Vacuole expands, pushing membrane against wall
  3. Turgor pressure increases, firming the cell
  4. Cell wall limits excessive expansion
• What happens to a plant cell in a concentrated solution?

  • Water exits the cell
  • Cell shrinks (plasmolysis)
  • Turgor pressure decreases
  • Plant may wilt
• What is the significance of turgor pressure in plants?

  • Maintains cell structure and firmness
  • Supports plant growth
  • Aids in nutrient transport
  • Prevents wilting