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7 Cards in this Set
- Front
- Back
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What 4 things need to be interchanged between an organism and its environment? |
Respiratory gases, nutrients, waste products and heat. |
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In what 2 ways can this exchange occur. |
(Passive) Diffusion and osmosis (Active) Active transport |
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In what ways are small organisms able to exchange efficiently. |
Large surface area to volume ratio Surface area is large enough compared to their volume. |
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How are organisms adapted to exchange if diffusion is the only transport method. |
Flat shape so that no cell is ever far from the surface, Specialised exchange surfaces with large surface areas to increase SA:V ratio. |
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What are the features of a specialised exchange surface. |
Large surface area, Short diffusion pathway, Steep concentration gradient maintained. |
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Define simple diffusion. |
The net movement of molecules from an area of high concentrations to an area of low conc. |
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Describe the changes when you inspire. |
External intercostal muscles contract, internal intercostal muscles relax. Ribs move up and out, Diaphragm contracts (flattens) Volume of the thorax increases. Air pressure in the lungs decreases. |
