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

What’s facilitated diffusion

Answer 2

Is a passive process. Relies only on inbuilt motion of the diffusing molecules. No external input from atp from respiration. It occurs down a concentration gradient

Question 3

What do carrier proteins do

Answer 3

A large molecule attaches to a carrier protein in the membrane

Then the protein changes shape

And releases the molecule on the opposite side of the membrane

Question 4

What do channel proteins do

Answer 4

They form pores in the membrane for charges particles to diffusion down their concentration gradient

Different channel proteins facilitate the diffusion of different charged particles

Question 5

State 3 factors that affect the rate of diffusion

Answer 5

Concentration gradient

Diffusion length /pathway

Thickness of exchange surface

Temperature

Question 6

Contrast facilitated diffusion and diffusion

Answer 6

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

Question 7

Explain why facilitated diffusion is a passive process

Answer 7

There is no ATP from respiration used in the process.

Only energy used in built energy of the molecules themselves