5.5 Osmosis Flashcards
What is osmosis?
Diffusion of water across a partially permeable membrane, from a dilute solution to a concentrated solution.
What is a solute?
A substance dissolved in a solvent, forming a solution
What is water potential?
The pressure exerted by water molecules as they collide with a membrane or container.
What is water potential measured in, and what is the symbol?
Measured in Pascals, and the symbol is Psi Ψ
What is the water potential of pure water?
0 Pa
What is the highest water potential?
0 Pa, only found in pure water.
What lowers the water potential?
The presence of a solute in water.
What leads to an increase in hydrostatic pressure?
An increase in volume of solution in a closed system.
What is hydrostatic pressure measured in?
Pascals (Pa)
What happens if the water potential outside of a cell is higher than the internal cell solution’s water potential?
The water will enter the cell by osmosis, increasing the hydrostatic pressure within the cell
What happens when water enters an ANIMAL CELL by osmosis?
The cell will swell, and if it cannot withstand the pressure, the cell-surface membrane will break, and the cell will burst (cytolysis)
What is cytolysis?
When a cell bursts due to excess water diffusing into the cell.
What happens if the water potential outside of a cell is equal to the internal cell solution’s water potential?
The water will exit and leave the cell at an equal rate, and there will be no change to the state of the cell.
What happens if the water potential outside of a cell is lower than the internal cell solution’s water potential?
The water will exit the cell.
What happens when water exits an ANIMAL cell by osmosis?
The cell’s volume is reduced, and the cell-surface membrane will “pucker”
