4.1 surface area to volume ratio Flashcards
1
Q
why do single-celled organisms not need a specialised gas exchange or transport system?
A
- diffusion distance is small
- large SA:Vol
- metabolic demands are low
2
Q
why do multicellular organisms need specialised gas exchange and transport systems/
A
- substances need to travel long distances to get from the outside to the cytoplasm
- need nutrients faster
- higher metabolic rate
3
Q
what are examples of specialised gas exchange systems?
A
- lungs
- gills
- tracheal system
- leaves
4
Q
what factors affect the rate of diffusion?
A
- surface area: the larger the SA the more particles can be exchanged at the same time
- concentration gradient: particles move from an area of high concentration to low
- diffusion distance: shorter the diffusion distance the faster diffusion can take place
5
Q
what are characteristics of mass transport systems?
A
- vessels (closed system)
- one directional
- transport medium (tissue fluid)
- maintenance of speed (pump/heart)
