SAT II Biology M : Lipids

Study concepts, example questions & explanations for SAT II Biology M

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Example Questions

Example Question #1 : Lipids

Phospholipids are an essential component of the phospholipid bilayer necessary to the cell.

Which of the following correctly represents a phospholipid subunit with the corresponding polarity?

Possible Answers:

Fatty acid head: nonpolar

Phosphate head: nonpolar

Fatty acid tail: nonpolar

Phosphate tail: polar

Fatty acid tail: polar

Correct answer:

Fatty acid tail: nonpolar

Explanation:

A phospholipid generally consists of a phosphate head (polar) and a fatty acid tail (non-polar).

Example Question #1 : Lipids

The phospholipid bilayer is critically important to the separation of the internal and external environment of the cell.

What drives the formation of the phospholipid bilayer?

Possible Answers:

None of these

The external environment pushes non-polar hydrophilic fatty acid tails to form the inner layer and the polar hydrophilic head groups to form the outer layer.

The external environment pushes non-polar hydrophobic fatty acid tails to form the inner layer and the polar hydrophilic head groups to form the outer layer.

The external environment pushes non-polar hydrophilic fatty acid tails to form the inner layer and the polar hydrophobic head groups to form the outer layer.

The external environment pushes non-polar hydrophobic fatty acid tails to form the inner layer and the polar hydrophobic head groups to form the outer layer.

Correct answer:

The external environment pushes non-polar hydrophobic fatty acid tails to form the inner layer and the polar hydrophilic head groups to form the outer layer.

Explanation:

The external hydrophilic environment attracts polar hydrophilic phosphate head groups to the exterior, while allowing non-polar hydrophobic fatty acids to remain shielded in the interior of what becomes the phospholipid bilayer.

Example Question #2 : Lipids

Lipids are made up of hydrocarbons linked to each other. 

A hydrocarbon involves an atom of carbon with how many hydrogen atoms bonded to it?

Possible Answers:

One

Five

Two

Four

Three

Correct answer:

Two

Explanation:

A hydrocarbon is made up of a carbon and two hydrogen atoms attached to it.

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