Feature of exchange surfaces aiding passive and active transport

Question 1

Increased surface area

Answer 1

Non-specialised: A flattened shape increases surface area and reduces diffusion distance
Specialised exchange surface: external=gills of tadpoles internal= alveoli

Question 2

Thin membrane surface

Answer 2

Short diffusion distance

Question 3

Concentration gradient

Answer 3

One is needed for diffusion to occur

Question 4

How is mass transport brought about?

Answer 4

Pressure differences

Question 5

How does mass transport happen in the xylem?

Answer 5

Evaporating water causes tension (negative pressure) pulling water up through the xylem

Question 6

How does mass transport happen in the phloem?

Answer 6

ATP is used to move sucrose into the phloem tube from the companion cell

Question 7

How does mass transport happen in mammalian circulation

Answer 7

High pressure is created by pumping of heart

Question 8

How does mass transport happen in mammalian ventilation?

Answer 8

Low pressure in thorax brings air into the lungs and vice versa

Question 9

What factors affect gaseous exchange?

Answer 9

Size of Surface Area
Moist surface into which gases dissolve
A diffusion path
Permeability to O2 and CO2

Question 10

State Fick’s Law

Answer 10

All values after p sign is of membrane:

Diffusion rate∝ SA of x Difference in concentration/thickness