Question 1

Which of the following best describes the reaction by which biological polymers such as proteins and polysaccharides are synthesized in cells?

Accepted Answer

Condensation (dehydration) reactions, which remove water to form bonds between monomers.

Question 2

Which of the following statements about protein structure is CORRECT?

Accepted Answer

The primary structure of a protein is the sequence of amino acids from the N-terminus to the C-terminus.

Question 3

Which of the following amino acids is unique because it does NOT have an asymmetric α-carbon atom?

Accepted Answer

Glycine

Question 4

A mutation causes a proline residue to be inserted into the middle of an α-helix. What is the most likely effect?

Accepted Answer

The α-helix will be disrupted, introducing a bend at the proline site.

Question 5

Which of the following bonds or interactions is primarily responsible for stabilizing the secondary structure of proteins?

Accepted Answer

Hydrogen bonds between NH and CO groups of the polypeptide backbone

Question 6

Which of the following best describes the difference between a motif and a domain in protein structure?

Accepted Answer

A motif is a supersecondary structure that may serve different functions in different proteins, while a domain is a tertiary structure with a specific function that can be independent of the rest of the protein.

Question 7

Which of the following is TRUE regarding the structure of DNA?

Accepted Answer

DNA is a double-stranded helix with antiparallel strands held together by hydrogen bonds between complementary bases.

Question 8

Which of the following statements about polysaccharides is CORRECT?

Accepted Answer

Glycogen is a highly branched storage polysaccharide found in animal cells.

Question 9

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

Accepted Answer

Mammals lack enzymes that can hydrolyze β(1→4) glycosidic bonds found in cellulose.

Question 10

Which of the following is a function of cholesterol in animal cells?

Accepted Answer

It is a major component of plasma membranes and helps regulate membrane fluidity.

Question 11

A patient is diagnosed with a genetic disorder that prevents the formation of disulfide bonds in proteins. Which level(s) of protein structure would be most directly affected?

Accepted Answer

Tertiary and quaternary structure

Question 12

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

Accepted Answer

They have a hydrophilic head and two hydrophobic tails.

Question 13

Which of the following is a correct pairing of a nucleotide base with its complementary base in DNA?

Accepted Answer

Adenine pairs with thymine via two hydrogen bonds.

Question 14

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

Accepted Answer

The presence of double bonds introduces bends in the hydrocarbon chain, preventing tight packing.

Question 15

Which of the following is a real-life example of a protein with quaternary structure?

Accepted Answer

Hemoglobin, which consists of two α and two β subunits.

Question 16

Which of the following best describes the directionality of nucleic acid synthesis?

Accepted Answer

Nucleic acids are synthesized in the 5' to 3' direction.

Question 17

Which of the following is a function of glycolipids in the plasma membrane?

Accepted Answer

Facilitating cellular recognition and maintaining membrane stability.

Question 18

Which of the following best explains why starch and cellulose, both polymers of glucose, have such different properties?

Accepted Answer

Starch is composed of α-D-glucose with α(1→4) linkages, while cellulose is composed of β-D-glucose with β(1→4) linkages.

Question 19

Which of the following is a correct statement about the role of molecular chaperones in protein folding?

Accepted Answer

Molecular chaperones assist in the proper folding of polypeptides and assembly of multimeric proteins.

The Macromolecules of the Cell: Structure, Function, and Organization

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