Biology Chapter 8

Front 1

Homeostasis -

Back 1

maintenance of stable internal conditions in a changing environment

Front 2

One way a cell maintains homeostasis is by...

Back 2

controlling the movement of substances across the cell membrane

Front 3

The cell membrane is made of...

Back 3

phospholipids

Front 4

Phospholipid -

Back 4

specialized lipid made of a phosphate head and two fatty acid tails

Front 5

Lipid Bilayer -

Back 5

phospholipids form a double layer and make the cell membrane

Front 6

Only _____ can pass through the lipid bilayer

Back 6

certain substances

Front 7

Only ____, ____ substances can pass through the cell membrane

Back 7

small, nonpolar

Front 8

In a solution, randomly moving molecules tend to fill up a space. When that space is filled up evenly, a state of _____ is reached

Back 8

equilibrium

Front 9

Concentration -

Back 9

the amount of a particular substance in a given volume

Front 10

Concentration Gradient -

Back 10

when one area has a higher concentration than another's

Front 11

Diffusion -

Back 11

movement of substances down a concentration gradient

Front 12

Simple Diffusion -

Back 12

movement in which small, nonpolar molecules can pass directly through the lipid bilayer

Front 13

Facilitated Diffusion -

Back 13

transport proteins help these substances diffuse through the cell membrane

Front 14

Osmosis -

Back 14

water can diffuse across a selectively permeable membrane

Front 15

Hypertonic -

Back 15

solution that has a higher solute concentration than the cytoplasm does; water moves out of cell

Front 16

Isotonic -

Back 16

solution that has the same solute concentration that the cytoplasm does; water diffuses in and out of cell equally

Front 17

Hypotonic -

Back 17

solution that has a lower solute concentration than the cytoplasm does; water moves into the cell

Front 18

Active Transport -

Back 18

requires energy to move substances against their concentration gradients

Front 19

Sodium-Potassium Pump -

Back 19

carrier protein that actively transports three sodium ions out of the cell and two potassium ions into the cell.