Question 1

Which property of carbon makes it especially suitable as the backbone of organic molecules essential for life?

Accepted Answer

It can form up to four covalent bonds, allowing for diverse and stable molecular structures.

Question 2

During the formation of a protein polymer from amino acid monomers, which type of reaction occurs and what is a byproduct?

Accepted Answer

Dehydration synthesis; $$\mathrm{H_2O} is $$released

Question 3

A patient is unable to digest starch but can digest glucose. Which type of chemical bond is the patient likely unable to break?

Accepted Answer

Glycosidic bonds

Question 4

Which functional groups are present in all monosaccharides and are critical for their reactivity and solubility?

Accepted Answer

Hydroxyl and carbonyl groups

Question 5

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

They are amphipathic, with hydrophilic heads and hydrophobic tails.

Question 6

A mutation changes a nonpolar amino acid in a protein to a charged amino acid. Which level of protein structure is most likely to be directly affected first?

Accepted Answer

Tertiary structure

Question 7

Which of the following statements correctly distinguishes DNA from RNA?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 8

Which of the following best describes the role of hydrogen bonds in the secondary structure of proteins?

Accepted Answer

They form between the amino and carboxyl groups of the polypeptide backbone.

Question 9

Which of the following is NOT a function of carbohydrates in living organisms?

Accepted Answer

Catalyzing chemical reactions

Question 10

A scientist observes the breakdown of a biological polymer in a test tube. Which of the following must be added to facilitate this reaction?

Accepted Answer

Water, to promote hydrolysis

Question 11

Which of the following best explains why cellulose is a good structural material in plants but not digestible by most animals?

Accepted Answer

Cellulose is composed of $$\beta-$$glucose monomers linked by $$\beta-1$$,4-glycosidic bonds, which most animals lack enzymes to hydrolyze.

Question 12

Which of the following correctly matches a macromolecule with its monomer?

Accepted Answer

Carbohydrate – Monosaccharide

Question 13

Which of the following is a key difference between fats (triglycerides) and phospholipids?

Accepted Answer

Phospholipids have two fatty acid tails and a phosphate group, while fats have three fatty acid tails and no phosphate group.

Question 14

Which of the following best describes the structure of a nucleotide?

Accepted Answer

A phosphate group, a five-carbon sugar, and a nitrogenous base

Question 15

Which of the following statements about the directionality of nucleic acids is correct?

Accepted Answer

Nucleic acids have a 5' phosphate end and a 3' hydroxyl end, and new nucleotides are added to the 3' end.

Question 16

A protein loses its function after being exposed to high heat. Which level(s) of protein structure are most likely disrupted?

Accepted Answer

Secondary, tertiary, and quaternary structures

Question 17

Which of the following best explains why DNA is more stable than RNA?

Accepted Answer

DNA lacks a hydroxyl group at the 2' position of its sugar, making it less susceptible to hydrolysis.

Question 18

Which of the following is NOT a component of a phospholipid?

Accepted Answer

Monosaccharide

Question 19

Which of the following best describes the process of hydrolysis in biological systems?

Accepted Answer

It breaks a covalent bond in a polymer by adding a water molecule.

Question 20

A researcher is studying a molecule with the formula $$C_{6}H$$_{12}$$O_{6}$. Which class of macromolecule is this most likely to be, and what is its primary function in cells?

Accepted Answer

A monosaccharide; energy source

Carbon, Carbohydrates, Proteins, Lipids, and Nucleic Acids: Foundations of Biological Macromolecules

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