DIFFUSION

Question 1

definition of diffusion

Answer 1

the net movement of molecules / ions from a region of higher concentration to a region of lower concentration down a concentration gradient
a form of passive transport

Question 2

what factors affect diffusion

Answer 2

concentration gradient
surface area
length of diffusion pathway

Question 3

how does conc gradient affect diffusion

Answer 3

the greater the gradient difference, the faster the rate of diffusion

Question 4

how does surface area affect diffusion

Answer 4

the larger the SA , the aster the rate of diffusion

Question 5

how does length of diffusion pathway affect diffusion

Answer 5

the thinner the exchange surface , the faster the rate of diffusion

Question 6

what is ficks law

Answer 6

rate of diffusion ∝ area of surface x diff in conc
——————————————-
thickness of surface over which
diffusion takes place

Question 7

what other factors may effect rate of diffusion

Answer 7

nature of plasma membrane ( what its made from , how many proteins are in it)
size and nature of diffusing molecule

Question 8

what is facilitated diffusion

Answer 8

passive process
occurs down a concentration gradient
requires proteins for the molecule to travel down , thus , only occur at specific points on the plasma membrane

Question 9

channel proteins

Answer 9

water filled protein, allowing water - soluble ions to pass through
without it , ions will pass through at a very slow rate
highly selective channels , only opening when specific ion is present

Question 10

carrier proteins

Answer 10

intrinsic protein that spans the membrane bilayer
]molecule using carrier proteins to pass through must bind to the protein
protein alters its shape, allowing the molecule to be released on the other side