Exchange

Question 1

Three factors affecting gas exchange

Answer 1

Distance
Surface area to volume ratio
Concentration

Question 2

Single cellular organisms

Answer 2

Exchange materials by diffusion with their environment
The need for a short diffusion path limits the size of a single cellular organism
A large sa:vol short diffusion distance

Question 3

Ficks law

Answer 3

Rate of diffusion = sa x conc / diffusion distance

Question 4

Multi cellular organism

Answer 4

-organisms larger than 1mm are multicellular
-larger organisms hav all evolved adaptions with a large sa:vol
-most have specialised exchange systems in

Question 5

Lungs

Answer 5

Highly vascolorised
Sacs connected to the pharynx
Air is drawn into them by a ventilation mechanism
Found in all air breathing vertebrates

Question 6

Gill structure

Answer 6

-gills are in a cavity on the side of a fish’s head
-four pairs of gills arches on each side
-on each arch are two series of stacked gill filaments splashed out as a v
-disc like projections called gill lamallae are on the upper and lower surface of each gillfilament

Question 7

Trachea

Answer 7

Supported by cartilage to prevent collapse on inhalation
Goblet cels secrete mucus
Cilliated epithelium moves dirty music up and out of the airways

Question 8

Bronchi

Answer 8

Similar structure to trachea
Amount of cartilage decreases as they get smaller

Question 9

Alveoli

Answer 9

Very thin epethilium for gas exchange
Collagen for support
Elastin to allow stretch and recoil to maximise ventilation

Question 10

Bronchioles

Answer 10

Walls ,axe or muscle which can constrict narrowing the bronchioles and controlling the air flow to the ackeoli
Lined by epithelia cells

Question 11

Xerophytes

Answer 11

Species of plant that has adapted to survive in an environment with little liquid water

Question 12

Adaptation of xerophytes

Answer 12

Thick cuticle
Small leaf surface area to volume ratio
Stomata sunken in pits
Leaf hairs
Rolled leaves