Unit 2 Cell Structre = Function: Module 11: Water Movement Osmosis Tonicity, and Osmoregulation

solutes

dissolved substances

molarity

molar concentations (mol/L); M

osmosis

the movement of water across a selectivly permeable memrane in response to a differnece in solute concentrations

water potential

to desciribe all of the chemical and physical forces that affetc the movement of water, such as osmosis, pressure, and gravity; helps to understand whether water moves into a ecell, or even up a tall tree

osmotic pressure

the tendency of water from one solution into another by osmosis

tonicity

used to describe osmotic pressure and the direction of water movement; describes how strongly water is pulled into one solution compared to another

hypertonic

solutuon is one higher solute concentration than another solutions

hypotonic

solution is one with a lower concentration than another solution

isotonic

solution has the same concentration as another slolution

contactile vacuoles

organellles that take up excess water from inside the cell and then, by contraction, expel it into the external environment

pressure potential

the effect of pressure on the movement of water

solute potential

the effect of solutes on the movements of water

osmoregulation

is the regukation of somotic presssure inside cells and organisms; can be thought of as the regulaton of water content, which keeps internal fluids from becoming too conentrated (high osmotic pressure) or too dilute (low osmotic pressure)

osmoconformers

some animals kep their internal fluids at the same osmotic pressure as the surrounding envrionemtn

osmoregulators

second way animals achieve water and electroylite homeostasis is by maintaing an interal solte concentration that is diffeernt from that of the environemt