Module 10 + 11 AP Biology Flashcards

the way molec. are distributed and causes net movement

net movement stops but movement of molecules in both directions continues

active maintenance of a stable environment w/ in cells

occurs when molecules move across membrane by diffusion

cell does not need to expand any energy to take in or remove substances, only works from high to low concentrations

diffusion across cell membrane through a transport protein, molec. moves through transport protein in cell membrane

first type, provides opening between inside and outside of the cell only certain molec. can pass depending on shape and charge

2nd type, binds to and then transports specific molec. across the cell membrane

water channels that allow water to enter or exit the cell by facilitated diffusion

low to high movements of substances against concentration gradient

cells use ATP directly to move molec. across the cell membrane

cells use ATP indirectly to move molec. across the cell membrane

process of vesicle fusing w/ cell membrane and releases its contents to the extracellular space

process when vesicle buds off from the cell membrane toward the cell interior, enclosing material from outside the cell and bringing it onto the cell

dissolved substances

liquid substances that dissolve solutes

concentration of a solute in a solution

membrane allows water or solutes to diffuse through it

blocks diffusion of water and solutes entirely

allows the movement of some molec. but not others

movement of water across a selectively permeable membrane in response to difference in solute concentration

describes all chemical and physical forces that affect the movement of water (osmosis, pressure, and gravity)

tendency of water to move from one solution into another by osmosis

pressure that gravity exerts on the solution

describes osmotic pressure and direction of water movement (how strongly water is pulled into one solution compare to another)

higher solute concentration than another solution

lower concentration than another concetration

same concentration as another solution

organelles that take up excess water from inside the cell and by contraction expel it onto external envrionment

force exerted by water pressing against object

measure of all factors that influence the movement of water (potential energy of water compared to reference)

effect of pressure on movement of water

effect of solutes on movement of water

regulation of osmotic pressure inside cells and organisms

animals that keep internal fluids at the same osmotic pressure as surrounding environment

expend considerable energy pumping ions across cell membranes to regulate the movement of water into and out of bodies