OsmosisSWBAT describe how osmosis affects the homeostasis of a cell

Starter

• What is diffusion? Give an example.

• What do the following prefixes mean?– Iso– Hyper– Hypo

• Can a fresh-water fish survive in the ocean? Can an ocean fish survive in fresh water?Why or why not?

Osmosis

• Osmosis is the diffusion of water across a membrane

• Water molecules move from high concentration (where there’s more water) to low concentration (where there’s less water)

• Remember: “Water follows salt!”

Situations Affecting Osmosis• The amount of dissolved solute in the substance

around a cell determines the direction water moves

• Isotonic: Substance and cell have the same amount of dissolved solute

• Hypertonic: Substance has more dissolved solute than cell

• Hypotonic: Substance has less dissolved solute than cell

Effects of Osmosis on CellsSubstance Description Effect on Cell

Isotonic

Hypertonic

Hypotonic