B1.10 - Exchanging Materials Flashcards
If the surface area : volume ratio is large ….
- Distance for diffusion is short
- simple diffusion can take place
- e.g 6:1
Small objects have what kind of SA:V
A large sa:v ratio
Larger organisms have what kind of sa:v ratiop
Smaller ratio
Smaller ratio in larger organisms means
- distances get bigger
- simple diffusion become insufficient
As the organisms grow..
- their sa:v ratio decreases
- becomes harder to exchange material quickly
- e.g Gases/food molecules will be unable to reach every cell in the organism by simple diffusion anymore
Adaptations for exchanging materials
- large surface area
- thin membrane
- efficient blood supply
- being ventilated
- villi
- stomata
Thin membrane advantage
Provides a short diffusion path
Efficient blood supply advantages
- moves diffusing substances away from exchange surfaces
- maintains a steep concentration gradient
Ventilation advantages
- makes gas exchange more efficient
- maintains steel concentration gradient
Villi advantages
-increases surface area
Stomata advantage
- allows Gases to diffuse in and out of leaf
- large surface area
- maintains steep concentration gradient
Adaptations of small intestine
- villi = increases surface area
- villi’s great blood supply = maintains concentration gradient
- thin membrane of villi =short diffusion distance
Adaptations of lungs
millions of alveoli:
- increases surface area
- good blood supply = maintains concentration gradient
- thin membrane = short diffusion distance
Adaptations of gills in a fish
each gill is made of gill filaments ( thin plates):
-increase surface area
Gill filaments are covered with lamella:
- increases surface area more
- good blood supply = maintains concentration gradient as water flow the opposite direction
- thin membrane = short diffusion distance
Adaptations of roots of a plant
Root surface is covered in millions of root hair cells:
- increasing surface area
- present on mature parts of the root
- absorb water/minerals from soil
