Question 1

Which property of carbon most directly explains its ability to form the diverse and complex molecules necessary for life?

Accepted Answer

Its ability to form up to four covalent bonds with other atoms, allowing for a variety of stable structures.

Question 2

A scientist is studying the breakdown of glycogen into glucose monomers in muscle cells. Which chemical process is responsible for this reaction, and what is a key feature of this process?

Accepted Answer

Hydrolysis; water is used to break the bonds between monomers.

Question 3

Which of the following best describes the structural difference between starch and cellulose, and how does this difference affect their biological function?

Accepted Answer

Starch has α-glycosidic linkages, making it digestible by humans, while cellulose has β-glycosidic linkages, making it indigestible for most humans.

Question 4

Which functional group is present in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-\mathrm{COOH})$$

Question 5

A mutation changes the order of amino acids in a protein. Which level of protein structure is directly affected by this mutation?

Accepted Answer

Primary structure

Question 6

Which of the following best explains why proteins can form a greater diversity of three-dimensional shapes than nucleic acids?

Accepted Answer

Proteins are made from 20 different amino acids with diverse R-groups, while nucleic acids are made from only 4 types of nucleotides with similar backbones.

Question 7

During the formation of a peptide bond between two amino acids, which chemical process occurs and what is released?

Accepted Answer

Dehydration synthesis; water ($$\mathrm{H}_2\mathrm{O}) is $$released.

Question 8

Which of the following best describes the backbone of a nucleic acid polymer?

Accepted Answer

It consists of alternating sugar and phosphate groups joined by phosphodiester bonds.

Question 9

Which type of chemical interaction is primarily responsible for the secondary structure (α-helix and β-sheet) of proteins?

Accepted Answer

Hydrogen bonding between the carboxyl ($$\mathrm{C}=\mathrm{O}) $$and amino ($$\mathrm{N}-\mathrm{H}) $$groups of the polypeptide backbone.

Question 10

A protein is composed of four separate polypeptide chains. Which level of protein structure does this describe?

Accepted Answer

Quaternary structure

Question 11

Which of the following statements about nucleotides is correct?

Accepted Answer

They can form hydrogen bonds between complementary nitrogenous bases, stabilizing the double helix structure of DNA.

Question 12

Which of the following best explains why cellulose is not digestible by most animals, including humans?

Accepted Answer

Humans lack the enzyme to break β-glycosidic linkages found in cellulose.

Question 13

Which of the following is a correct description of the 5’ and 3’ ends of a nucleic acid strand?

Accepted Answer

The 5’ end has a free phosphate group, and the 3’ end has a free hydroxyl group.

Question 14

A patient is diagnosed with a genetic disorder that causes misfolding of a critical enzyme. Which property of proteins is most directly affected by this misfolding?

Accepted Answer

The three-dimensional shape, which determines the enzyme’s active site and function.

Question 15

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction in which two monomers are joined together by removing a molecule of water ($$\mathrm{H}_2\mathrm{O}).$$

Question 16

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

Accepted Answer

A carboxyl group ($$-\mathrm{COOH})$$

Question 17

Which of the following best explains why DNA strands are described as antiparallel?

Accepted Answer

One strand runs in the 5’ to 3’ direction, while the other runs in the 3’ to 5’ direction.

Question 18

Which of the following is a correct pairing of a purine and a pyrimidine in DNA?

Accepted Answer

Adenine (purine) pairs with Thymine (pyrimidine) via hydrogen bonds.

Question 19

Which of the following best describes the role of R-groups in protein structure?

Accepted Answer

They interact to determine the tertiary structure of the protein.

Question 20

Which of the following statements about hydrolysis is correct?

Accepted Answer

It is the process by which polymers are broken down into monomers by the addition of water ($$\mathrm{H}_2\mathrm{O}).$$

Biomolecules: Carbohydrates, Proteins, and Nucleic Acids – Structure and Function

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