ShmoopTube

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Here’s your shmoop du jour, brought to you by nutrients…

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…so much healthier for you than oldtrients. [woman eating food and face turns green]

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Maybe clean out the fridge once in a while…

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Why is the surface area to volume ratio of cells important?

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And here are the potential answers: To say that the ratio is NOT important in

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the exchange of materials between the cell and its environment is just oh so wrong.

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The ratio between the surface area and volume of cells has a gigantic impact on the behavior,

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physiology and other qualities of their environment.

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Like when your lungs expand and contract to take in oxygen and release carbon dioxide. [lungs expanding and contracting]

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So, breathe easy, Shmoopers, Answer D is incorrect. [a couple with their arms out wide on a beach]

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Answer C is also suspect.

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Size and shape affect the ability of diffusion to supply the demands of the cell.

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Having an equal surface area-to-volume ratio would inhibit the necessary flow of materials

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across plasma membranes.

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Cells need breathing room to diffuse more oxygen and take in the nutrients they crave. [a cell struggling to breathe]

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Answer C is not the ratio that cells have in mind for a peaceful existence.

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So is a smaller surface area to volume ratio better than a large ratio?

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Or is it better the other way around?

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Remember that surface area is very important to cell function because everything the cell [Inside of a cell with arrow showing nutrients enter here]

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could possibly want makes its way through the cell membrane.

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As the size of a cell decreases, the ratio of surface area to volume increases. [a green cell decreasing in size]

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As a result, small cells are more efficient at diffusion because of their high surface [one green cell multiplies into 5 cells]

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area to volume ratio.

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A long, thin cell like a nerve cell is a perfect example of efficiency.

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On the other side of the coin, when a cell increases in size, the surface area expands [A green cell increasing in size]

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at a lower rate than the volume.

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Based on that, the correct answer is B, the larger the ratio, the better the cell is at

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exchanging material with its environment.

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It also explains why protozoa should never be the size of a school bus. [A protozoa bus picking up school girls]

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They would starve to death because they would have a hard time getting enough oxygen, water

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and nutrients transported across their plasma membranes. [Gigantic cell destroying a city with laser vision]

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Besides…like the creators of Godzilla won't need any more inspiration for their horror movies…

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