Chapter 3

Question 1

allowing some substances to cross and preventing others from crossing

Answer 1

selectively permeable

Question 2

a protein that plays a role in the active or passive movement of specific substances through the cell membrane

Answer 2

transport proteins

Question 3

a layer composed of lipids, has hydrophobic tails

Answer 3

lipid bilayer

Question 4

the movement of a substance down its concentration gradient from a more concentrated area to a less concentrated area

Answer 4

diffusion

Question 5

diffusion of water, the movement of water from low concentration to high concentration

Answer 5

osmosis

Question 6

a difference in the concentration of a substance over a distance

Answer 6

concentration gradient

Question 7

the diffusion of a substance through a biological membrane

Answer 7

passive transport

Question 8

the movement of a substance through a membrane against concentration gradient

Answer 8

active transport

Question 9

the spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane, down their concentration gradients

Answer 9

facilitated diffusion

Question 10

the cellular uptake of materials in which the plasma membrane engulfs extracellular materials

Answer 10

endocytosis

Question 11

the release of macro molecules from a cell by the fusion of vesicles with the plasma membrane

Answer 11

exocytosis