Exchange and Transport

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  • Created by: Alice
  • Created on: 28-05-14 11:32
What four things are exchanged between an organism and its environment?
Respiratory gases like Oxygen and CO2, Nutrients like glucose, fatty acids, amino acids, vitamins/minerals, Excretory products - urea, CO2, and Heat.
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What are the two ways that exchange takes place?
Passively - diffusion and osmosis. Actively - with energy - Active Transport.
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Name the five features of specialised exchange surfaces and explain what they contribute to.
Large SA: VOL ratio - fast diff rate. Thin - short diff path - fast diff rate. Partially permeable membrane - selective, easy diffusion. Movement of external medium - air - maintain conc grad. Movement of internal medium - blood- maintain conc grad.
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Describe how to work out SA: VOL ratio.
Surface area = length squared. May need to multiply by number of faces if shape is 3D. Volume = length cubed. Divide surface area by volume.
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How have organisms evolved to overcome slow diffusion from large volume?
Flattened shape, no cell ever far from surface. Specialised exchange surface with large areas to increase SA: VOL ratio. Lungs in mammals, gills in fish.
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Other cards in this set

Card 2

Front

What are the two ways that exchange takes place?

Back

Passively - diffusion and osmosis. Actively - with energy - Active Transport.

Card 3

Front

Name the five features of specialised exchange surfaces and explain what they contribute to.

Back

Preview of the front of card 3

Card 4

Front

Describe how to work out SA: VOL ratio.

Back

Preview of the front of card 4

Card 5

Front

How have organisms evolved to overcome slow diffusion from large volume?

Back

Preview of the front of card 5

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