Exchange between organisms and their environment

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What does a higher SA:V ratio mean in terms of the rate of gas exchange?
Higher SA in comparison to V = better, quicker rate of exchange
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Why do large organisms need a specialised gas exchange system?
Organisms get larger, volume increases quicker than surface area. As a result, simple diffusion can only works for relatively inactive organisms-it would take too long for substances to reach centre of organism if diffusion=sole transport method
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Why would an organism have a flattened shape?
no cell is ever far from the surface
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Name five features of specialised exchange surfaces
1 ^ SA:V-increase exchange rate 2 thin-reduce diffusion distance&rapid crossing of exchange surface 3 selectively permeable 4 movement of environmental medium(air)-maintain diffusion gradient 5 movement of internal medium-maintain diffusion gradient
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Why are specialised exchange surfaces often found inside an organism?
They are often very thin and therefore easily damaged and dehydrated - they need to be protected
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Card 2

Front

Why do large organisms need a specialised gas exchange system?

Back

Organisms get larger, volume increases quicker than surface area. As a result, simple diffusion can only works for relatively inactive organisms-it would take too long for substances to reach centre of organism if diffusion=sole transport method

Card 3

Front

Why would an organism have a flattened shape?

Back

Preview of the front of card 3

Card 4

Front

Name five features of specialised exchange surfaces

Back

Preview of the front of card 4

Card 5

Front

Why are specialised exchange surfaces often found inside an organism?

Back

Preview of the front of card 5

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