movement across a cell membrane

importance of cell transport

1. required for cell homeostasis

2. transport of waste in and out the cell

3. absorption of nutrients into the cell

4. oxygen for respiration

5. CO2 exit

diffusion

the movement of particles from a high to low concentration; passive transport

simple diffusion

the diffusion of nonpolar, small molecules through the cell membrane without the help of a channel protein; with the concentration gradient

facilitated diffusion

the diffusion of polar, large, charged molecules through the cell membrane with the help of a channel protein; with the concentration gradient

osmosis

diffusion of water across a semipermeable membrane from high water concentration to low water concentration; passive transport

hypotonic

cell grows because water enters it; water goes where there is more solute, however the cell can swell and burst

contractile vacuole

pumps water out the cell; the solution to a cell that might burst from an excess of water

hypotonic plant cell

turgid (full); cell wall protects cell from bursting

hypertonic

cell shrinks because water leaves it; the cell can shrivel and die

cell pumps out solute

the solution to a cell that is drastically shrunken

hypertonic plant cell

plasmolysis (wilt); can recover from this

isotonic

no difference in concentration of water between cell and environment; cell is in equilibrium and volume is stable

isotonic plant cell

flaccid

paramecium

can survive severe hypotonic solutions

shellfish

hypertonic

IV solution/saline

isotonic

endocytosis

process by which the cell take sin molecules into the intracellular space; requires formation of a vesicle for bulk import of substances

pinocytosis

type of endocytosis; to drink

phagocytosis

type of endocytosis; to eat

exocytosis

process by which cells release molecules into the extracellular space; requires formation of a vesicle for bulk export of substances