Lesson 2 - Diffusion and Facilitated Diffusion

Question 1

meaning diffusion

Answer 1

the net movement of particles of a liquid or gas from an area of high concentration to an area of low concentration, down the concentration gradient. This is a passive process, so does not require ATP

Question 2

how does diffusion occur

Answer 2

due to the random motion of molecules due to the thermal energy they have, dependent on temperature

Question 3

when does diffusion stop

Answer 3

until both areas are uniformly distribution

Question 4

meaning facilitated diffusion

Answer 4

involves proteins in the membrane that only allows specific substances to move through passively down the concentration gradient

Question 5

name 2 types of mechanisms of facilitated diffusion

Answer 5

channel protein, carrier protein

Question 6

state the difference between channel and carrier proteins

Answer 6

channel proteins are openings in the centre, and can be gated, whilst carrier proteins chnage shape to allpws

Question 7

what are the conditions needed for passive transport of molecules to occur

Answer 7

molecules need to be moved from an area of high concentration to a low concentration down the concentration gradient. No energy is needed

Question 8

why can’t water and ions pass through the protein pores like oxygen and carbon dioxide

Answer 8

Water can’t pass across the hydrophobic region in the middle of the membrane, and ions are not lipid-soluble and are charged