2.1.5 diffusion

Question 1

define simple diffusion

Answer 1

the net movement or molecules from an area of higher concentration to one of lower concentration

Question 2

explain how simple diffusion occurs

Answer 2

particles have KE in liquid + gaseous state
move randomly until uneven distribution becomes even
move at high speeds and collide constantly

Question 3

is diffusion faster over shorter or longer distances? why?

Answer 3

shorter distances
particles colliding will slow down overall movement
over longer distances more collisions occur = slows down

Question 4

what factors affect the rate of simple diffusion?

Answer 4

concentration gradient = larger diff in conc means faster rate of diffusion
temperature = higher temp means more KE so particles diffuse faster

Question 5

explain how diffusion across a membrane happens?

Answer 5

particles pass through phospholipid bilayer
can only occur is membrane is permeable to the particles

Question 6

describe the permeability of the phospholipid bilayer

Answer 6

hydrophobic interior repels charged atoms
most permeable to small hydrophobic particles
impermeable to charged mols + ions

Question 7

what factors affect the rate of diffusion across a membrane?

Answer 7

surface area = larger area to dissuse means higher rate of diffusion
membrane thickness = thinner mem means faster diffusion

Question 8

describe the process of facilitated diffusion

Answer 8

movement of mols down a conc gradient using carrier and channel proteins
makes membrane semi permeable

Question 9

what factors affect rate of facilitated diffusion?

Answer 9

conc gradient = steepr gradient means faster rate
number of proteins = more proteins means faster rate
temp = higher temp means faster rate
surface area = greater SA + thinner mem means faster rate