biological membranes part 2

Question 1

biological membranes

Answer 1

selectively permeable

Question 2

active transport

Answer 2

requires chemical energy (ATP); low to high

Question 3

passive transport

Answer 3

does not require chemical energy (ATP); high to low

Question 4

concentration gradient

Answer 4

where energy for passive transport comes from, the difference in concentration of a substance across space

Question 5

diffusion

Answer 5

the process of random movement toward equilibrium

Question 6

diffusion rate depends on

Answer 6

-size and mass of molecules or ions: smaller molecules diffuse faster
-temperature of the solution: higher temps equals faster diffusion
-density of the solution: low density equals faster diffusion
-concentration gradient: steeper gradient equals faster diffusion
-area and distance: short distance and large surface area equals faster diffusion

Question 7

osmosis

Answer 7

diffusion of water; direction depends on the relative concentrations of water molecules

Question 8

isotonic

Answer 8

equal solute concentrations

Question 9

hypertonic

Answer 9

higher solute concentration outside cell

Question 10

hypotonic

Answer 10

lower solute concentration outside shell

Question 11

aquaporins

Answer 11

water can cross membranes through special channels

Question 12

ion channels

Answer 12

channel proteins with hydrophilic pores

Question 13

gated

Answer 13

can be closed or open to ion passage

Question 14

facilitated diffusion

Answer 14

polar and charged molecules diffuse with concentration gradients, but facilitated by protein channels or carriers

Question 15

channel proteins

Answer 15

integral membrane proteins that form a tunnel

Question 16

carrier proteins

Answer 16

-membrane proteins that bind some substances and speed their diffusion through the bilayer
-transport polar molecules—glucose, across membranes in both directions