[Campbell Biology P.130] Which of the following statements best describes the primary differ... | Practice Question
Which of the following statements best describes the primary difference between tertiary and quaternary protein structures?
A: Tertiary structure involves interactions between side chains of a single polypeptide, while quaternary structure involves the aggregation of multiple polypeptide subunits.
B: Tertiary structure is stabilized by covalent bonds only, whereas quaternary structure is stabilized by non-covalent bonds.
C: Quaternary structure is present in all proteins, while tertiary structure is found only in some.
D: Tertiary structure determines the overall shape of the polypeptide, while quaternary structure determines its amino acid sequence.
Explanation
Tertiary structure refers to the overall three-dimensional shape of a single polypeptide chain, stabilized by interactions between its side chains. Quaternary structure, on the other hand, describes the aggregation of two or more polypeptide chains subunits into one functional macromolecule.