Diffusion

Question 1

Diffusion def

Answer 1

The net movement of particles from an area of high concentration to an area of low concentration.

Question 2

Factors affecting diffusion

Answer 2

Temp
Pressure
Concentration gradient
Surface area

Question 3

Passive process

Answer 3

Doesn’t require energy to diffuse

Question 4

Simple Diffusion

Answer 4

• Molecules must be lipid soluble and small to diffuse across the membrane.
• Passive
• All particles in constant motion due to kinetic energy
• Motion is random
• Occurs until equilibrium is reached.
• only occurs in liquids and gases.

Question 5

Fick’s Law

Answer 5

Diffusion is proportional to the difference in concentration between two regions (the concentration gradient)

Question 6

Active Diffusion

Answer 6

• Requires ATP
• Active transport
• Bulk transport : endo and exo-cytosis

Question 7

Facilitated Diffusion

Answer 7

Used for large polar (not lipid soluble) molecules charged ions.

Passive - but molecules use proteins instead of passing between the phospholipids.

2 types of proteins: carrier proteins and channel proteins.

Question 8

Carrier proteins

Answer 8

Molecules that are complimentary with the protein bind on causing the carrier protein to change shape to force the molecule through the membrane.

Doesn’t require ATP/energy.

Transport example: glucose

Question 9

Protein channel

Answer 9

Protein embedded all the way through the phospholipid bi-layer.

The hollow tube fills with water to allow water soluble ions/molecules to dissolve and pass through the channel.

Selective

Question 10

Osmosis

Answer 10

The movement of water from a region of heighten water potential to a region of lower water potential over a partially-permeable membrane.

Question 11

Water potential

Answer 11

The pressure created by water molecules.

Measured in kPa

Pure water has a water potential of zero.

Water potential cannot be positive +

Question 12

Isotonic solution

Answer 12

When the water potential of the solution and the cell within the solution is the same =

Question 13

Hypertonic

Answer 13

When the water potential of the cell is more positive than the solution and therefore the water potential for the cell would be higher.

Question 14

Hypotonic

Answer 14

When the water potential of the solution is more positive than the cell and therefore the water potential for the solution would be higher.

HypOtonic like H2O which pure water has the highest water potential.