Question 1

Which of the following best describes the chemical reaction responsible for the synthesis of biological polymers such as proteins and polysaccharides?

Accepted Answer

Condensation (dehydration) reaction, which removes water to form bonds between monomers.

Question 2

A protein is found to have a mutation that replaces a cysteine residue with a serine. Which level of protein structure is most likely to be directly affected by this mutation?

Accepted Answer

Primary structure, because the amino acid sequence is changed.

Question 3

Which of the following bonds or interactions is primarily responsible for stabilizing the secondary structure of proteins such as α helices and β sheets?

Accepted Answer

Hydrogen bonds between backbone NH and CO groups

Question 4

Hemoglobin is a tetrameric protein composed of two α and two β subunits. Which level of protein structure does this illustrate?

Accepted Answer

Quaternary structure

Question 5

Which of the following amino acids would most likely be found on the surface of a soluble globular protein?

Accepted Answer

Glutamate

Question 6

Which of the following statements about the directionality of polypeptides is correct?

Accepted Answer

Amino acid sequences are conventionally written from the N-terminus to the C-terminus.

Question 7

Which of the following best explains why mammals cannot digest cellulose?

Accepted Answer

Mammals lack enzymes that hydrolyze β(1→4) glycosidic bonds.

Question 8

A mutation causes a protein to lose all of its ionic bonds but retain its disulfide and hydrogen bonds. Which level(s) of protein structure could still be maintained?

Accepted Answer

Primary and secondary structure

Question 9

Which of the following is a correct description of the difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 10

Which of the following best describes the complementary base pairing in DNA?

Accepted Answer

A pairs with T via two hydrogen bonds; G pairs with C via three hydrogen bonds.

Question 11

Which of the following is a function of molecular chaperones in the cell?

Accepted Answer

They aid in the proper folding of other proteins.

Question 12

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

Accepted Answer

They contain double bonds that introduce bends, preventing tight packing.

Question 13

A patient is diagnosed with a genetic disorder that prevents the formation of sphingolipids. Which cellular structure or function is most likely to be affected?

Accepted Answer

Formation of lipid rafts in the plasma membrane

Question 14

Which of the following is true regarding the structure of starch and glycogen?

Accepted Answer

Both are composed of α-D-glucose units linked by α(1→4) and α(1→6) glycosidic bonds.

Question 15

Which of the following best describes the amphipathic nature of phospholipids?

Accepted Answer

They have both hydrophilic and hydrophobic regions.

Question 16

Which of the following is a real-world consequence of the presence of trans fats in the human diet?

Accepted Answer

Trans fats increase the risk of heart disease and elevate cholesterol levels.

Question 17

Which of the following statements about protein domains is correct?

Accepted Answer

A domain is a discrete, locally folded unit of tertiary structure with a specific function.

Question 18

Which of the following best explains why the primary structure of a protein is important genetically?

Accepted Answer

It is specified by the order of nucleotides in the corresponding mRNA.

Question 19

Which of the following is a correct statement about the formation of peptide bonds?

Accepted Answer

Peptide bonds are covalent bonds formed between the carboxyl group of one amino acid and the amino group of another.

The Macromolecules of the Cell: Structure, Function, and Biological Importance

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