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Science

Osmosis

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Osmosis is the movement of water from a high water concentration to a low water concentration through a partially permeable membrane. Osmosis takes place in all living cells.

Plants absorb water from the soil by osmosis through their root hair cells. Plants use water for several vital processes including photosynthesis and transporting minerals.

Osmosis

Osmosis is one of the most challenging ideas in GCSE biology. You need to understand a particle model and be able to use it to explain this special type of diffusion that takes place through partially permeable membranes – membranes that let small particles pass through but not large particles.

Osmosis explains how water moves from high water concentration to low water concentration through a partially permeable membrane.

You need to remember:

  • the direction of movement of water
  • the effect of water movement on the volume and therefore the pressure of the different solutions
  • that particles move in both directions through the membrane. Changing the pressure or the concentration on one side of the membrane will change the movement of the particles until equilibrium is reached.

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