Biology·Organisation & maintenance · NSSCO 3.3.2

Osmosis

Narrated lesson · press play

The special diffusion of water across a partially permeable membrane — why plant cells go turgid or flaccid, why animal cells burst or shrink, and how turgor pressure holds a plant up.

What you'll learn in this lesson

By the end you should be able to (NSSCO Biology 3.3.2):

  • Understand the effect of osmosis on cells
  • Describe osmosis as the movement of water across a partially permeable membrane, down a water potential gradient
  • Describe the effects of osmosis on animal and plant tissues (hypotonic, isotonic and hypertonic solutions)
  • Use the terms turgor pressure, turgid, flaccid and plasmolysis
  • Explain the importance of water potential and osmosis in the uptake of water by plants
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Miss Rachel and Mike talk through the whole topic — with the figure and working drawn live.

Hands-on lab
Investigate osmosis in potato cylinders in 3D
Osmosis · NSSCO Biology · namstudy