cells transport

concentration

the amount of a solute (such as an ion, sugar, or gas) dissolved in a given volume of solvent or solution

concentration gradient

the gradual difference in the concentration of solutes (dissolved particles) between two regions in a space or across a cell membrane

passive transport

• Does not require the input of metabolic (cellular) energy

• Moves particles from an area of high concentration to an area of low concentration (down or with the concentration gradient)

active transport

• Requires the direct input of energy to move particles from regions of low concentration to regions of high concentration.

 

simple diffusion

• Transport through membrane, no transport protein used

• Particles must be small, nonpolar, uncharged

facilitated diffusion

• Transport protein used

• Particles are large, polar, or charged

osmosis

• Diffusion of water across a selectively permeable membrane

• Usually facilitated by aquaporins

auqaporins

have positively charged amino acids in the channel to help water cross

osmolarity

•  the number of particles of solute per liter of solution

• Measures solute concentration for all solutes

  • High osmolarity = high concentration of solute

  • Low osmolarity = low concentration of solute

tonicity

• the relative difference in osmolarity in different compartments

• Terms usually used to describe the external environment, but could also be used to describe the cell

isotonic

solution has an equal concentration of solute to the cell

hypotonic

solution has a lower concentration of solute than the cell has

hypertonic

solution has a higher concentration of solute than the cell has

plasmosis

cell membrane shrinks away from the cell wall

osmoregulation

maintenance of water balance, which allows organisms to control their internal solute composition and water potential

lysis

burst

crenation

cells shriveled

turgid

cell pushes on cell wall

flaccid

a plant cell that is limp, floppy, or lacks internal turgor pressure because there is no net movement of water into the cell