exchange Flashcards
(10 cards)
What happens to the surface area to volume ratio (SA:V) as an organism gets larger?
It decreases.
Why can small organisms rely on diffusion for exchange?
They have a high surface area to volume ratio.
Why do larger organisms need specialised exchange surfaces?
Because their low SA:V ratio means diffusion alone is not sufficient.
What is the surface area to volume ratio of a cube with 1 cm sides?
6:1
Name three key features of efficient exchange surfaces.
Thin walls, large surface area, moist surface.
What is an example of an external exchange surface?
Gills of young tadpoles.
What is an example of an internal exchange surface?
Alveoli in mammalian lungs.
How do flatworms perform gas exchange?
Through diffusion across their flat body surface.
Why must gas exchange surfaces be moist?
So gases can dissolve and diffuse easily.
Where are nutrient exchange surfaces located in mammals?
Inside the body, like in the villi of the ileum.
