Osmosis

• Osmosis is the movement of water through a  partially permable membrane.

• Osmosis needs no energy from the cell

• It diffuses water from high water concentration (dilute)  to low water concentration (more concentrated).

• Membranes which only let some types of particles through.

• They let water move across them (osmosis)

• Diffusion refers to the movement of any particles from a region of hight to low concentration

• Osmosis only refers to the movement of water molecules

• It helps maintain constant internal conditions, and restores balance in the cells

If a cell uses up water in chemical reactions

• the cytoplasm becomes more concentrated and more water immediatly moves in by osmosis

• if too much water moves in, the cell will swell and may burst

If more water is produced in a cells chemical reactions

• The cytoplasm becomes more dilute and water leaves the cell by osmosis

• when water moves out of the cell, theres a risk of the cytoplasm getting too concentrated, shrivel up, and can no longer survive

• Plants rely on osmosis to support their stem and leaves

• Water moves into the plant cells causing the vacuole to swell and press the cytoplasm against the cell walls

• This builds up until no more water can enter the cell, making the plant hard and rigid.