Exchange Surfaces Summary
Presentation
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Biology, Science
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9th Grade
•
Medium
Samantha Argent
Used 10+ times
FREE Resource
6 Slides • 6 Questions
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Exchange Surfaces Summary
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Exchange Surfaces
Tiny organisms, like bacteria, can rely solely on diffusion to get all the nutrients they need to survive.
Multicellular organisms cannot rely on diffusion alone, they require these specialised surfaces.
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Multiple Choice
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Surface Area to Volume Ratio
Bacteria can rely on diffusion alone to get all of the nutrients that they need to survive as they have a large surface area to volume ratio.
Multicellular organisms cannot rely on diffusion as they have a small surface area to volume ratio.
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Calculating SA:vol
SA / vol
vol / vol
If we look at the middle example...
SA / vol = 24 / 8 = 3
vol / vol = 8 / 8 = 1
SA:vol = 3:1
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Multiple Choice
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Multiple Choice
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Open Ended
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Multiple Choice
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Multiple Select
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The villi in the small intestines is a specialised exchange surface. Explain how it is well adapted for the diffusion of nutrients. (6)
The small intestines (SI) are highly folded and include villi which both increase the surface area of the SI.
The lining of the villi are only one cell thick which decreases the diffusion distance.
The rich blood capillary network maintains a steep diffusion gradient by removing nutrients and transporting them around the body as they are absorbed.
The increased surface area, reduced diffusion distance and maintaining a concentration gradient all increase the rate of diffusion.
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