SA:V Ratio and Exchange surfaces Flashcards
How do unicellular organisms get oxygen into the cell?
Unicellular organisms exchange substances through diffusion.
It’s got a large enough surface area to volume ratio to do so
What are large organism’s surface area to volume ratio like?
Large organisms have a small surface area to volume ratio.
They haven’t got a big enough surface area to provide for a big volume
How is a larger surface area to volume ratio useful for organisms?
If an organism has a large surface area to volume ratio, the more efficient diffusion will be.
How is a larger surface area to volume ratio useful for organisms?
If an organism has a large surface area to volume ratio, the more efficient diffusion will be.
Explain how surface area to volume ratio works.
Using an example of a hippo vs a mouse.
- A hippo has a larger volume than a mouse.
This means its surface area to volume ratio is smaller as the surface area is not large enough to provide for such a big organism. - A mouse has a smaller volume.
This means it has a larger surface area to volume ratio as substances can reach the organelles a lot quicker.
What are the adaptations of a root hair cell?
- Large surface area to move mineral ions by active transport/ diffusion and water by osmosis.
- Contains lots of mitochondria for movement of minerals using energy.
What are the adaptations of the alveoli?
- Folded structure: bigger surface area to volume ratio.
- Good blood supply: mantains concentration gradient (capilaries)
- Thin wall, decrease diffusion distance
What are the adaptations of the small intestine ?
- Folded structure: Large surface area to volume ratio (covered in microvilli)
- Good blood supply
- Thin wall, decrease diffusion distance.
- Very long - increase the time for absorption…
Give 3 adaptations of the gills in fish.
- Gill fillaments give folded structure/ Fillaments covered in lamellae : Large surface area.
- Gill fillaments have good blood supply (from lamellae)
-Gill fillaments have thin wall to decrease diffusion pathway.
How do animals sort the problem of having a small surface area to volume ratio?
- Having special structures for gas ecchange.
- Having a tranpsort system
What is the meaning of a large surface area to volume ratio?
It means that a large area is folded to fit into a small space(volume).
State the name of the gas exchange surface in fish.
- Gills
Explain the adaptation of the gill fillaments.
- Large surface area to increase the rate of diffusion.
What are gill fillaments covered in?
- Gill fillaments are covered in lamellae.
How is the water that leaves the fish different to the water that enters?
- Water that leaves has more CO₂ from fish respiring.
- Less oxygen
What are gill fillaments?
- Gill fillaments are thin plates that form the gills.
What is an exchange surface?
- A part of an organism where substances are exchanged with the envrionment.
Explain how substances diffuse in a leaf (for photosynthesis….)
- CO₂ and water vapour diffuses into stomata
- O₂ diffuse out stomata
How does water diffuse out of a leaf?
- It evaporates
- Escapes by diffusion
Why do spongy mesophyll cells have an irregular structure?
- Leads to air gaps –> gas can travel
What cells are transparent to allow light to reach the palisade cells?
- Upper epidermal cells
What covers the epidermis of the leaf?
A waxy cuticle layer
Why does the epidermis have a waxy cuticle?
- So H₂0 doesn’t evaporate.
What 4 things increase the effectiveness of an exchange surface?
- Large surface area
- Thin membrane
- Good blood supply
- Being ventilated (for gas exchange)
