exchanging substances Flashcards
1
Q
how are alveoli specialised to maximise the diffusion of O2 and CO2
A
large surface area- there is more area to diffuse making it quicker
very thin walls- a short diffusion pathway
a good blood supply- maintains a high concentration of O2 to CO2 so the diffusion rate is faster
2
Q
how are villi specialised to maximise the diffusion
A
large surface area- digested food is absorbed quicker into the blood
a single layer of surface cells- short diffusion pathway
a good blood supply- to maintain a high concentration of O2
3
Q
where does co2 diffuse through a leaf
A
stomata
4
Q
where does o2 and water vapour diffuse out of a leaf
A
stomata
5
Q
why are guard cells important in a leaf
A
they control how open or closed the stomata are to prevent water loss and the plant wilting and dying
