Ap Bio Ch. 7 Vocab

Front 1

amphipathic molecule

Back 1

a molecule that has both a hydrophilic region and a hydrophobic region

Front 2

aquaporin

Back 2

a transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis)

Front 3

concentration gradient

Back 3

an increase of decrease in the density of a chemical substance in an area. Calls often maintain concentration gradients of ions across their membranes. When a gradient exists, the ions or other chemical substances involved tend to movie from where they are more concentrated to where they are less concentrated

Front 4

cotransport

Back 4

the coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient

Front 5

electrochemical gradient

Back 5

the diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential

Front 6

flaccid

Back 6

limp. a walled cell is this in surroundings where there is no tendency for water to enter.

Front 7

gated channel

Back 7

a protein channel in a cell response membrane that opens or closes in response to a particular stimulus

Front 8

hypertonic

Back 8

in comparing two solutions, referring to the one with a greater solute concentration

Front 9

hypotonic

Back 9

in comparing two solutions, referring to the one with a lower solute concentration

Front 10

isotonic

Back 10

having the same solute concentrations as another solution.

Front 11

ligan

Back 11

a molecule that binds specifically to a receptor sit of another molecule.

Front 12

phagocytosis

Back 12

a type of of endocytosis involving large, particulate substances, accomplished mainly by macrophages, neutrophils, and dendritic cells.

Front 13

pinocytosis

Back 13

a type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

Front 14

tonicity

Back 14

the ability of a solution to cause a cell within to gain or lose water.

Front 15

turgid

Back 15

very firm. a walled cell becomes this if it has a greater solute concentration than its surroundings, a resulting in entry of water.

Front 16

membrane potential

Back 16

the charge difference between a cell's cytoplasm and the extracellular fluid, due to the differential distribution of ions. membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.