Diffusion

Question 1

define diffusion

Answer 1

the net movement of molecules or ions from a region where they are more highly concentrated to one where their concentration is lower until evenly distributed.

Question 2

why is simple diffusion described as passive?

Answer 2

it doesn’t need any outside sources of energy to

Question 3

what is facilitated diffusion?

Answer 3

a passive process relying on the on inbuilt motion (kinetic energy)of the diffusing molecules and only happens at specific points on the plasma membrane.

Question 4

which proteins are involved in facilitated diffusion?

Answer 4

carrier proteins and protein channels

Question 5

state three factors that affect the rate of diffusion

Answer 5

concentration gradient / area over which diffusion takes place / thickness of exchange surface / temperature

Question 6

contrast between facilitated diffusion and diffusion

Answer 6

Facilitated diffusion only occurs at channels on the membrane where there are special protein carrier molecules.

Question 7

glucose molecules are transported into cells through the pores in the proteins that span the phospholipid bilayer. explain why they do not pass easily through the phospholipid bilayer.

Answer 7

There is no ATP from respiration used in the process. The only energy used is the in-built (kinetic) energy of the molecules themselves