chapter 7

Question 1

active transport

Answer 1

transport across a membrane using energy (usually in the form of ATP)

Question 2

amphipathic

Answer 2

molecules, containing hydrophobic (“water-fearing) and hydrophilic (“water-loving”) regions

Question 3

aquaporins

Answer 3

membrane proteins that allow the passage of water molecules

Question 4

carrier proteins

Answer 4

change structure when molecules bind to shuttle them across the membrane

Question 5

channel proteins

Answer 5

a tunnel through the membrane

Question 6

concentration gradient

Answer 6

the region along which the density of a chemical substance increases or decreases

Question 7

cotransport

Answer 7

occurs when active transport of a solute indirectly drives transport of other substances

Question 8

diffusion

Answer 8

the movement of particles of any substance so that they spread out evenly into the available space

Question 9

electrochemical gradient

Answer 9

the combined forces of chemical and electrical that drive the diffusion of ions across a membrane

Question 10

electrogenic pump

Answer 10

a transport protein that generates voltage across a membrane storing energy that can be used for cellular work

Question 11

endocytosis

Answer 11

macromolecules are taken into the cell in vesicles

Question 12

exocytosis

Answer 12

when transport vesicles migrate to the membrane, fuse with it and release their contents outside the cell

Question 13

flaccid

Answer 13

limp

Question 14

fluid mosaic model

Answer 14

membrane structure depicts the membrane as mosaic of protein molecules bobbing fluid bilayer of phospholipids

Question 15

gated

Answer 15

channels that open or close in response to a stimulus

Question 16

glycolipids

Answer 16

carbohydrates bonded to lipids

Question 17

glycoproteins

Answer 17

carbohydrates bonded to proteins

Question 18

hypertonic

Answer 18

a solution in which a solute concentration is greater outside than inside (the cell is hypotonic)

Question 19

hypotonic

Answer 19

a solution in which solute concentration is greater than outside (the cell is hypertonic)

Question 20

integral

Answer 20

penetrate the hydrophobic core

Question 21

ion channels

Answer 21

facilitate the transport of ions

Question 22

isotonic

Answer 22

a solution in which solute concentration is the same outside and inside

Question 23

membrane potential

Answer 23

the voltage across a membrane

Question 24

osmoregulation

Answer 24

control of solute concentration and water balane

Question 25

osmosis

Answer 25

the diffusion of free water across a selectively permeable membrane

Question 26

passive transport

Answer 26

diffusion of a substance across a biological membrane when no energy is expended

Question 27

peripheral proteins

Answer 27

bound to the surface of the membrane

Question 28

pinocytosis

Answer 28

molecules are taken up when extracellular fluid is 'gulped' into tiny vesicles

Question 29

plasmolysis

Answer 29

when the cell shrivels and the membrane pulls away from the cell wall in multiple locations

Question 30

receptor-mediated endocytosis

Answer 30

vesicle formation is triggered by solute binding to receptors

Question 31

soduim-potassium pump

Answer 31

energizes the transport of potassium into the cell and sodium out of the cell

Question 32

tonicity

Answer 32

the ability of a surrounding solute to cause a cell to gain or lose water

Question 33

transmembrane proteins

Answer 33

integral proteins that span the membrane

Question 34

transport proteins

Answer 34

proteins that provide the ability for hydrophilic molecules to cross the membrane

Question 35

turgid

Answer 35

very firm