Question 1

Which of the following best describes the core structure of a steroid?

Accepted Answer

A lipid with a core of four fused hydrocarbon rings

Question 2

Which functional group is always present at the C3 position of the steroid core structure?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 3

Cholesterol is classified as which type of biomolecule?

Accepted Answer

Steroid

Question 4

Which of the following is a direct function of cholesterol in animal cell membranes?

Accepted Answer

Regulating membrane fluidity

Question 5

At high temperatures, what is the effect of cholesterol on membrane fluidity?

Accepted Answer

Decreases membrane fluidity by restricting phospholipid movement

Question 6

At low temperatures, cholesterol prevents membranes from becoming too:

Accepted Answer

Rigid

Question 7

Which of the following statements about cholesterol is FALSE?

Accepted Answer

Cholesterol is a carbohydrate

Question 8

Which of the following structures is a sterol?

Accepted Answer

A molecule with a four-ring core and a hydroxyl group at C3

Question 9

Which of the following best explains why cholesterol is considered amphipathic?

Accepted Answer

It contains both a hydrophilic hydroxyl group and a hydrophobic hydrocarbon tail

Question 10

Which of the following is a direct consequence of cholesterol's presence in the plasma membrane at physiological temperature?

Accepted Answer

It reduces the movement of phospholipid fatty acid chains

Question 11

Which of the following best describes the effect of cholesterol on membrane fluidity at low temperatures?

Accepted Answer

It increases membrane fluidity by preventing fatty acid chain packing

Question 12

Which of the following is NOT a function of cholesterol?

Accepted Answer

Serving as a major energy storage molecule

Question 13

Which of the following statements about the steroid nucleus is correct?

Accepted Answer

It consists of three six-membered rings and one five-membered ring fused together

Question 14

Which of the following best explains why cholesterol is essential for animal cell membranes?

Accepted Answer

It modulates membrane fluidity across a range of temperatures

Question 15

A patient with a genetic defect that prevents cholesterol synthesis would most likely experience which of the following?

Accepted Answer

Impaired membrane fluidity and hormone synthesis

Question 16

Which of the following is a direct precursor of bile salts?

Accepted Answer

Cholesterol

Question 17

Which of the following best describes the effect of cholesterol on the permeability of the plasma membrane to small water-soluble molecules?

Accepted Answer

It decreases permeability by filling spaces between phospholipids

Steroids and Cholesterol: Structure, Function, and Membrane Roles

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