Question 1

Which of the following statements best explains why lipids are hydrophobic?

Accepted Answer

Lipids consist mostly of hydrocarbon chains, which are nonpolar and do not form hydrogen bonds with water.

Question 2

A triglyceride is formed by joining three fatty acids to one glycerol molecule. What type of reaction is responsible for this process?

Accepted Answer

Dehydration reaction

Question 3

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

Accepted Answer

Saturated fatty acids have the maximum number of hydrogen atoms and no double bonds, while unsaturated fatty acids have one or more double bonds.

Question 4

Why do unsaturated fats tend to be liquid at room temperature?

Accepted Answer

The presence of cis double bonds causes bending in the fatty acid chains, preventing tight packing.

Question 5

Which of the following is NOT a biologically important class of lipids?

Accepted Answer

Polysaccharides

Question 6

What is the primary function of adipose tissue in animals?

Accepted Answer

Long-term energy storage and insulation

Question 7

Phospholipids are essential components of cell membranes. Which structural feature allows them to form bilayers?

Accepted Answer

They have hydrophilic heads and hydrophobic tails, causing them to arrange in a bilayer with tails facing inward.

Question 8

Which of the following statements about cholesterol is correct?

Accepted Answer

Cholesterol is a steroid that is a precursor for other steroid hormones and is found in animal cell membranes.

Question 9

Which of the following is a function of proteins in living organisms?

Accepted Answer

Catalyzing chemical reactions, defense, transport, and structural support

Question 10

A peptide bond is formed between which two functional groups of amino acids?

Accepted Answer

Amino group and carboxyl group

Question 11

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in a polypeptide chain

Question 12

Enzymes are a type of protein that speed up chemical reactions. Which property allows enzymes to be reused in multiple reactions?

Accepted Answer

Enzymes are not changed by the reaction and can catalyze additional reactions.

Question 13

Which of the following equations represents the general dehydration reaction for forming a triglyceride?

Accepted Answer

$$\mathrm{Glycerol} + 3\ \mathrm{Fatty\ acids} \rightarrow \mathrm{Triglyceride} + 3\ \mathrm{H_2O}$$

Question 14

A patient is found to have high levels of plaque deposits in their arteries. Which type of dietary fat is most likely contributing to this condition?

Accepted Answer

Saturated fats from animal sources

Question 15

Which of the following best explains why trans fats are considered more harmful than saturated fats?

Accepted Answer

Trans fats are synthetically produced during hydrogenation and may contribute more to cardiovascular disease than saturated fats.

Question 16

Which of the following is true about the structure of phospholipids in cell membranes?

Accepted Answer

Phospholipids form a bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.

Question 17

Which of the following is NOT a function of proteins?

Accepted Answer

Storing genetic information

Question 18

A protein's function is most directly determined by which of the following?

Accepted Answer

Its amino acid sequence and three-dimensional structure

Question 19

Which of the following best describes the role of hemoglobin in the body?

Accepted Answer

Hemoglobin transports oxygen from the lungs to other parts of the body.

Chapter 5.3

Study Guide - Practice Questions