Biology

05. Determination of the solute potential by measuring the degree of incipient plasmolysis

  • 01:08 Why is the epidermis placed in de-ionised water at the start?
  • 01:18 Why do you leave the epidermis strips in the bathing solution for 30 minutes?
  • 01:31 Why do you add the same bathing solution to the epidermal strip on the slide?
  • 01:47 Why should you blot any excess liquid on the slide?
  • 02:19 Which concentration of sodium chloride solution produces 50% plasmolysed cells?
  • 02:37 What is the solute potential of this sodium chloride solution, which is equal to the solute potential of the onion cells?

  • white tile

  • fine forceps

  • scalpel

  • red onion

  • 5 x 9cm petri dishes / small bottles

  • deionised water

  • sodium chloride solution (0.2, 0.4, 0.6, 0.8 mol dm-3)

  • stopclock

  • microscope slides

  • cover slips

  • microscope

  • dropping pipette

  • paper towel

Hazard Risk Control measure

Scalpel

Cuts to skin

Cut down and away from body onto a white tile or chopping board