Diffusion

Question 1

Define simple diffusion

Answer 1

Passive process requires no energy from ATP hydrolysis

Net movement of small, lipid-soluble molecules directly through the bilayer from an area of higher concentration to an area of lower concentration

Question 2

Define facilitated diffusion

Answer 2

Passive process.

Specific channels or carrier proteins either complementary binding sites transports large and/or polar molecules (not soluble in hydrophobic phospholipid tail) across concentration gradient.

Question 3

Explain how channel and carrier proteins work

Answer 3

Channel: hydrophilic channels bind to specific ions= one side of the protein closes & the other opens
Carrier: bind to complementary molecule= conformation change releases molecule on other side of membrane; in facilitated diffusion, passive process; in active transport, requires energy from ATP hydrolysis Net

Question 4

Name 5 factors that affect the rate of diffusion

Answer 4

-temperature
-diffusion distance
-surface area
-size of molecules
-difference in concentration