Practice question · Estimate
A membrane at low temperature is stiffening toward a solid. Set the effect cholesterol has on its fluidity here, from -1 (reduces it further) to +1 (raises it back).
Estimate on a scale from Reduces fluidity (-1) to Raises fluidity (1).
Hints
- Cholesterol is a fluidity buffer, so its effect depends on the temperature.
- In the cold it wedges between tails and prevents the tight packing that would solidify the membrane.
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Why
In the cold cholesterol raises fluidity, giving , by wedging between tails and preventing tight packing. At high temperature it does the opposite, acting in both directions is precisely what makes it a buffer.
Practise Cell Membranes
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