Osmosis Flashcards
what is osmosis?
the net movement of water from an area of higher water potential to that of lower water potential, down the cg.
what is water potential?
the measure of the ability of water molecules to move freely in solution, the potential of water to diffuse in/out a solution.
what are aquaporins?
proteins which allow rapid movement of water across plasma membranes.
how come water molecules can diffuse across the phospholipid bilayer?
although they’re polar, they are very small.
what does pure water have a WP of?
zero. high water potential.
how does adding a solute affect potential?
it lowers it.
what is the potential of any solution?
always negative, the more negative it is, the higher the concentration of the solute.
what is an isotonic solution?
the same water potential in the solution as the cell, no overall movement, net movement is 0.
what is a hypotonic solution?
where there is a lower concentration of the solute compared to the cell, the solution has a higher WP than the cell so water will move into it.
what is a hypertonic solution?
when there is a higher concentration of the solute in the solution compared to the cell, so the solution has a lower water potential than the cell so water will move out of the cell.
how does the WP gradient affect the rate of osmosis?
the higher the gradient, the faster the rate. as osmosis occurs the difference in concentrations decreases so osmosis slows down.
