water potiental

• In which direction does water move by osmosis?

  From high water potential to low water potential
• What happens in a hypotonic external medium?


  • Water moves into the cell by osmosis
  • Cell swells; animal cells may burst (lysis)
  • Plant cells become turgid, supporting tissues
• What occurs in a hypertonic external medium?


  • Water moves out of the cell by osmosis
  • Animal cells shrink
  • Plant cells undergo plasmolysis, leading to wilting
• What is the effect of an isotonic external medium on cells?


  • No net movement of water
  • Animal cells maintain homeostasis
  • Plant cells become flaccid
• What is the term for when plant cells become turgid?

  Turgid
• What is plasmolysis in plant cells?

  When the cell membrane pulls away from the cell wall
• What is the method to determine water potential in beetroot cells?

  1. Prepare a sucrose solution of known concentration
  2. Immerse beetroot discs in the solution
  3. After 2 hours, collect a sample of the bathing solution
  4. Release a drop into original sucrose solution
  5. Record the direction and speed of movement
• What happens to beetroot cells in hypotonic or hypertonic media?

  They change the water potential of the external medium
• What occurs if the external sucrose solution is isotonic?

  No change in density occurs