Osmosis

• What is a hypotonic solution?

  A solution with a higher water potential than inside the cell
• What happens to animal cells in a hypotonic/dilute solution?

  They swell and eventually burst
• Why don't plant cells burst in a hypotonic/dilute solution?

  Their cell wall protects them
• What happens to plant cells in a hypotonic/dilute solution?

  They become turgid as their vacuole expands
• What is an isotonic solution?

  A solution with the same water potential as inside the cell
• What is a hypertonic solution?

  A solution with a lower water potential than inside the cell
• What happens to animal cells in a hypertonic/concentrated solution?

  They shrivel (shrink)
• What happens to plant cells in a hypertonic/concentrated solution?

  Their vacuole shrinks and the membrane may pull away from the cell wall
• What is plasmolysis in plant cells?

  When the plant cell membrane pulls away from the cell wall
• How does the water potential gradient affect the rate of osmosis?

  A higher gradient increases the rate
• How does membrane thickness affect the rate of osmosis?

  Thinner membranes increase the rate of osmosis
• How does surface area affect the rate of osmosis?

  Larger surface areas increase the rate of osmosis
• What happens to the water potential gradient as osmosis occurs over time?

  It decreases as the solutions become closer to isotonic
• Why does a larger surface area increase the rate of osmosis?

  More molecules can cross the membrane in the same amount of time
• How is water potential related to concentration?

  The more negative the water potential, the more concentrated the solution
• What protects plant cells from bursting in hypotonic solutions?

  The cell wall
• What is a solution?

  A mixture where one substance is dissolved into another
• What is a solvent?

  The liquid in which a solute is dissolved
• What is a solute?

  Substance that dissolves in a liquid
• Why does osmosis occur?

  At high WP, water molecules have more energy because they are less restricted by the presence of solutes. At low WP, water molecules have less energy because they are more restricted by the presence of solutes.
• What are the units of water potential?

  Kilopascals (KPa)
• Define osmosis.

  Osmosis is the net movement of water from an area of higher water potential to an area of lower water potential across a partially permeable membrane.