Diffusion

Question 1

Diffusion definition

Answer 1

Net movement of particles down a concentration gradient from a high concentration to a low concentration

Question 2

Type of movement

Answer 2

passive

Question 3

Polarity and charges in diffusion

Answer 3

Small, non-polar molecules rapidly diffuse across a membrane

Small, polar molecules diffuse across but much more slowly

Charged particles cannot diffuse across a membrane

Question 4

Fick’s law

Answer 4

rate of diffusion is proportional to:

surface area*difference in conc
/
length of diffusion path

Question 5

Rate is affected by…

Answer 5

Temperature
Concentration difference
Surface area
Diffusion distance
Size, shape and charge
Number of carrier/channel proteins present

Question 6

Types of diffusion

Answer 6

Simple

Facilitated - carrier and channel proteins

Question 7

Facilitated diffusion

Answer 7

PASSIVE

Happens due to protein molecules embedded un the membrane allow it to happen

Charged and polar molecules, Glucose, Amino acids

Question 8

How facilitated diffusion occurs

Answer 8

CHANNEL
Form pores in the membrane allowing charged molecules to move through
Different channel proteins needed for different charged particles

CARRIER
Large molecule attaches to carrier protein
Causes protein to change shape, releasing molecule to other side of membrane
Different carrier proteins needed for different shaped molecules