1.3.2 Osmosis

• Water potential is the measure of the relative tendency of water to move from one area to another
• Water moves from areas of high water potential to areas of low water potential through a membrane
• Match the membrane type with its characteristics:

  Semi-Permeable Membrane ↔️ Water, small non-polar molecules

  Permeable Membrane ↔️ All molecules
• The selective permeability of a semi-permeable membrane depends on molecule size and polarity.


  True
• Water and small non-polar molecules can pass through semi-permeable membranes.


  True
• What happens to an animal cell in an isotonic solution?

  No net water movement
• In a hypertonic solution, water flows out of the cell, causing it to shrink
• What happens to a cell placed in an isotonic solution?

  No change
• What is the effect of a hypertonic solution on a cell?

  Cell dehydration
• Osmosis involves the movement of water from a region of high water potential to low water potential.


  True
• High water potential indicates more free water molecules and fewer solutes
• A semi-permeable membrane maintains cellular homeostasis by restricting the movement of certain molecules.


  True
• Through what type of membrane does water move along the water potential gradient?

  Semi-permeable
• High water potential means more free water molecules and less solutes
• What is the net effect of a water potential gradient on water movement?

  Osmosis
• In a hypotonic solution, water flows into the cell causing it to swell, which can lead to lysis.


  True
• What happens to a cell in a hypotonic solution if it cannot withstand the pressure?

  It lyses
• In a hypertonic solution, water flows out of the cell, causing it to shrink
• Match the solution type with its effect on animal cells:

  Isotonic ↔️ No change

  Hypotonic ↔️ Swells/Bursts

  Hypertonic ↔️ Shrinks
• What is the risk associated with a hypotonic solution for animal cells?

  Cell lysis
• In an isotonic solution, there is no net movement of water because the water potential is equal inside and outside the cell.


  True
• What happens to an animal cell in a hypotonic solution?

  Water flows in, cell swells
• What is turgor pressure in plant cells and why is it important?

  Structural integrity
• Plant cells have a rigid cell wall that animal cells lack.

  True
• The semi-permeable cell wall and large vacuole allow plant cells to better regulate water balance through osmosis
• An isotonic solution has an equal concentration of solutes inside and outside the cell.


  True
• In a hypertonic solution, water flows out of the cell, leading to cell shrinkage
• What is the definition of osmosis?

  Net water movement
• A selectively permeable membrane allows all molecules to pass through.

  False
• What does the water potential gradient refer to?

  Difference in water potential
• Steps involved in osmosis based on water potential gradient

  1️⃣ Region of high water potential

  2️⃣ Region of low water potential

  3️⃣ Semi-permeable membrane

  4️⃣ Water movement
• Semi-permeable membranes are essential for osmosis and maintaining cellular homeostasis
• How does water move across a water potential gradient?

  From high to low
• The water potential gradient is the difference in water potential between two regions
• Match the solution type with its effects on animal cells:

  Isotonic ↔️ No change

  Hypotonic ↔️ Swells/Bursts

  Hypertonic ↔️ Shrinks
• In a hypotonic solution, water flows into the cell causing it to swell.


  True
• Why does water move during osmosis?

  Difference in water potential
• In a hypotonic solution, water flows into the cell because the water potential is lower inside
• Water moves through a selectively permeable membrane
• What happens to water concentration in a region of high water potential?

  It is high