2.8 Tonicity and Osmoregulation

• Tonicity refers to the relative concentration of solutes on either side of a semipermeable membrane
• What drives the movement of water across a semipermeable membrane?

  Difference in solute concentration
• High solute concentration corresponds to low water potential
• Match the tonicity type with its effect on animal cells:

  Hypertonic ↔️ Water moves out, cell shrinks

  Isotonic ↔️ No net water movement, cell maintains shape

  Hypotonic ↔️ Water moves in, cell swells and may burst
• In a hypotonic solution, water moves into the cell, causing it to become turgid
• Tonicity refers to the relative concentration of solutes
• In a hypotonic solution, water moves into the cell, causing it to become turgid
• Osmosis involves the movement of water across a semipermeable membrane
• Water will always move from areas of high water potential to areas of low water potential to achieve equilibrium
• Osmosis is crucial for maintaining cell volume.
• Tonicity refers to the relative concentration of solutes
• In an isotonic solution, there is no net movement of water across the cell membrane.

  True
• From which areas does water move to achieve equilibrium in osmosis?

  High to low water potential
• In a hypotonic solution, animal cells may swell and potentially lyse.
• Osmosis is essential for maintaining cell volume.


  True
• Why is osmoregulation necessary in hypertonic environments?

  Prevents cell shrinkage
• Freshwater organisms face the challenge of preventing excessive water intake.

  True
• What are the three types of tonicity?

  Hypertonic, isotonic, hypotonic
• Match the tonicity type with its definition:

  Hypertonic ↔️ Higher solute concentration outside the cell

  Isotonic ↔️ Equal solute concentration inside and outside the cell

  Hypotonic ↔️ Lower solute concentration outside the cell
• Arrange the effects of different tonicities on red blood cells:

  1️⃣ Hypertonic: Cells shrink (crenate)

  2️⃣ Isotonic: Cells maintain shape

  3️⃣ Hypotonic: Cells swell and may burst (lyse)
• In which direction does water move across a membrane to achieve equilibrium?

  High to low water potential
• Hypertonic conditions can lead to cell dehydration.


  True
• What type of membrane allows water to pass through but restricts solute movement?

  Semipermeable
• In a hypertonic solution, water moves out of the cell, causing it to shrink
• Osmosis is driven by the difference in water potential.


  True
• High solute concentration results in high water potential.

  False
• Plant cells do not burst in hypotonic solutions due to their rigid cell walls.


  True
• In an isotonic solution, the cell maintains its normal size
• Order the three types of tonicity from highest to lowest solute concentration outside the cell:

  1️⃣ Hypertonic

  2️⃣ Isotonic

  3️⃣ Hypotonic
• Osmosis is driven by the difference in water potential.
• Low solute concentration results in high water potential.

  True
• What happens to a plant cell in a hypertonic environment?

  Plasmolysis
• Osmoregulation is the process by which organisms maintain a stable internal water and solute concentration.
• Match the role of osmoregulation with its importance:

  Prevents Cell Bursting ↔️ Regulates water intake in low-solute environments

  Supports Cell Function ↔️ Ensures enzymes and cellular processes function efficiently

  Prevents Cell Shrinkage ↔️ Maintains cell hydration in high-solute environments
• In marine environments, organisms actively transport water and salts to conserve water.