Question 1

Which of the following best explains why saturated fatty acids are solid at room temperature, while unsaturated fatty acids are typically liquid?

Accepted Answer

Saturated fatty acids have no double bonds, allowing their hydrocarbon tails to pack tightly together.

Question 2

A triglyceride molecule is formed by the bonding of which components?

Accepted Answer

Three fatty acids and one glycerol molecule

Question 3

Which structural feature distinguishes a steroid from other types of lipids?

Accepted Answer

A rigid backbone of four fused carbon rings

Question 4

Why do unsaturated fatty acids have a bent shape?

Accepted Answer

The presence of one or more double bonds in the hydrocarbon chain

Question 5

Which of the following is a function of waxes in biological systems?

Accepted Answer

Restricting water loss and protecting against pests on plant leaves

Question 6

Which lipid is the most common steroid found in animal cell membranes and is a precursor for other important molecules?

Accepted Answer

Cholesterol

Question 7

What is the primary reason that phospholipids form bilayers in water?

Accepted Answer

They have hydrophilic phosphate heads and hydrophobic fatty acid tails.

Question 8

Which of the following best describes the difference between a phospholipid and a triglyceride?

Accepted Answer

A phospholipid contains two fatty acids and a phosphate group, while a triglyceride contains three fatty acids.

Question 9

Which of the following is a real-world consequence of the structure of unsaturated fatty acids?

Accepted Answer

Vegetable oils remain liquid at room temperature due to the bent shape of their fatty acid tails.

Question 10

Which of the following best explains why waxes are water-resistant?

Accepted Answer

Waxes are composed of long fatty acid tails and alcohols that pack tightly, making them nonpolar and hydrophobic.

Question 11

Which of the following is NOT a function of steroids in animals?

Accepted Answer

Forming waterproof layers on leaves

Question 12

A scientist analyzes a lipid and finds it contains a rigid structure of four fused carbon rings. Which class of lipid is this molecule most likely to belong to?

Accepted Answer

Steroids

Question 13

Which of the following statements about fatty acids is correct?

Accepted Answer

Fatty acids consist of a carboxyl group attached to a hydrocarbon chain.

Question 14

Which of the following best describes the molecular difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have only single bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

Question 15

Which of the following is a direct consequence of the amphipathic nature of phospholipids in biological membranes?

Accepted Answer

They spontaneously form bilayers with hydrophobic tails facing inward and hydrophilic heads facing outward.

Question 16

Which of the following is a correct statement about the role of cholesterol in animal cell membranes?

Accepted Answer

Cholesterol helps maintain membrane fluidity and stability.

Question 17

Which of the following best explains why honeybees use wax to build honeycombs?

Accepted Answer

Wax is firm, water-resistant, and provides a safe place to raise larvae and store honey.

Question 18

Which of the following is a real-world example of the function of waxes in animals?

Accepted Answer

Waxes help protect and lubricate skin and hair in mammals.

Question 19

Which of the following is a correct statement about the structure of triglycerides?

Accepted Answer

Triglycerides are composed of three fatty acids bonded to a glycerol molecule.

Question 20

Which of the following is a function of phospholipids in biological systems?

Accepted Answer

Forming the structural foundation of cell membranes

Lipids: Structure, Types, and Biological Functions

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