Ch 4 Membrane Transport

Question 1

plasma membrane

Answer 1

serves as physical barrier between cell and interstitium. regulates movement in and out of cell, establishes and maintains electrochemical gradient, functions in cell communication

Question 2

passive transport

Answer 2

depends of substances moving down concentration gradient, no energy

Question 3

active transport

Answer 3

substances moved up concentration gradient, requires energy

Question 4

diffusion

Answer 4

net movement of a substance from area of greater concentration to lower concentration. continues until substance reaches equilibrium

Question 5

equilibrium

Answer 5

molecules evenly distributed throughout a given area

Question 6

what does rate of diffusion depend on

Answer 6

concentration gradient and temperature

Question 7

simple diffusion

Answer 7

small nonpolar solutes pass between phospholipid bilayer, unregulated by plasma membrane. movement depends on concentration gradient

Question 8

facilitated diffusion

Answer 8

small polar or charged solutes assisted by plasma membrane

Question 9

channel mediated diffusion

Answer 9

movement of small ions between water filled protein channels (leak and gated)

Question 10

leak channels

Answer 10

always open channels in the plasma membrane

Question 11

gated channels

Answer 11

open in response to stimuli for a fraction of a second

Question 12

carrier mediated diffusion

Answer 12

small polar molecules assisted across membrane by carrier proteins down the concentration gradient

Question 13

uniporter

Answer 13

carrier transporting only one substance

Question 14

osmosis

Answer 14

movement of water between selectively permeable membrane, NOT SOLUTES. either slips between phospholipid bilarer or through aquaporins

Question 15

aquaporins

Answer 15

integral water channels in membrane

Question 16

isotonic solution

Answer 16

water to solute concentration is the same inside cell as in solution

Question 17

hypertonic solution

Answer 17

higher concentration of solute outside the cell, causing water to move out of the cell

Question 18

hypotonic solution

Answer 18

higher concentration of solute inside the cell, causing water to move inside the cell

Question 19

hydrostatic pressure

Answer 19

pressure exerted by a fluid on the inside wall of its container

Question 20

exocytosis

Answer 20

vesicle inside cell traps molecules, joins up with phospholipid bilayer and releases

Question 21

endocytosis

Answer 21

cellular membrane forms pockets to intake large molecules

Question 22

phagocytosis

Answer 22

membrane engulfs and breaks aparts things not wanted or needed inside cell

Question 23

pinocytosis

Answer 23

membrane pinches off, molecules get trapped inside