passive transport: diffusion

Question 1

passive transport: diffusion

diffusion is due to what?

Answer 1

random motion and collision of molecules (not a pulling or pushing force)

Question 2

passive transport: diffusion

what is the movement of diffusion?

Answer 2

movement down a concentration gradient

from area of high concentration to area of low concentration

Question 3

what is simple diffusion?

Answer 3

nonpolar and lipid-soluble substances, diffusing directly through the lipid bilayer

Question 4

facilitated diffusion

Answer 4

larger, polar molecules

Question 5

in facilitated diffusion, transported substances bind to what? give examples

Answer 5

carrier proteins or pass through protein channels

e.g., glucose, amino acids, and ions

Question 6

what factors affect diffusion rates?

Answer 6

distance

molecule size
(smaller substances diffuse faster than larger substances)

temperature
(heat increases rate of diffusion)

gradient
(greater the difference in concentration of 2 substances, the greater the rate of diffusion)

electrical force

Question 7

simple diffusion

what are some materials which diffuse directly through cell membrane?

Answer 7

lipid-soluble compounds
(alcohols, fatty acids, and steroids)

dissolved gases (oxygen and carbon dioxide)