Water Potential in Cells Flashcards
what is water potential?
a measure of the concentration of free water molecules in a solution
what is the water potential of pure water?
zero
what happens to water potential when a solute is added?
- water potential falls as there will be a lower concentration of free water molecules - concentrated solutions have a very low water potential
how does osmosis link to water potential?
in osmosis, water moves from an area of high water potential to an area of lower (more negative) water potential
why do animal and plant cells react differently to being placed in different concentrations?
- free water molecules are constantly moving in and out of cells
- this is because plant cells have a cell wall which can withstand a large amount of water pressure
what is an isotonic solution?
the solution outside the cell has the same water potential as inside the cell - no net movement
what is a hypotonic solution?
the solution outside the cell has a higher water potential then inside the cell - net movement of free water molecules into the cell
what is a hypertonic solution?
the solution outside the cell has a lower water potential then inside the cell - net movement of free water molecules out of the cell
why do plants wilt?
plants wilt because there is not enough water to fill their cells and therefore the cytoplasm shrinks from the cell wall
