1
Q
why do single-celled organisms not need specialised transport systems?
A
they have:
- a large SA:V ratio
- a low metabolic activity
2
Q
what features do an effective exchange system have?
A
- increased surface area
- thin layers
- good blood supply
- good ventilation
3
Q
how does an increased surface area improve gas exchange?
A
provides a larger area for gaseous exchange to occur over
4
Q
how do thin layers improve gas exchange?
A
provides a short diffusion distance which makes gaseous exchange faster
5
Q
how does a good blood supply improve gas exchange?
A
provides a steep concentration gradient which means faster diffusion
6
Q
how does good ventilation improve gas exchange?
A
maintains a steep concentration gradient
