Identify true statements of cholesterol and its fluidity.

1. cholesterol decreases membrane fluidity in areas called rafts, which contain large amounts of sphingolipids and cholesterol.
2. cholesterol inhibits crystallization that would otherwise occur in membranes rich in unsaturated fatty acids.
3. cholesterol is generally buried in a bilayer, with its planar rings oriented toward the solvent and its hydroxyl group aligned with the fatty acid tails of the bilayer.
4. cholesterol increases membrane fluidity that otherwise contains mostly long chain saturated fatty acids.

The correct answer is 2. Cholesterol inhibits crystallization that would otherwise occur in membranes rich in unsaturated fatty acid.

Explanation:

Cholesterol is a complex lipid and also an important constituent of plasma membrane.Cholesterol regulates the membrane fluidity in both high and low temperature.

    At high temperature cholesterol increases the melting point for stabilizing the membrane and in low temperature cholesterol interacts with adjacent phospholipids thus result to prevent crystallization.

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sio2 (quartz)

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.