Tertiary structure is defined as:
A) the sequence of amino acids.
B) the folding of a single polypeptide chain in three-dimensional space.
C) hydrogen bonding interactions between adjacent amino acid residues into helical or pleated segments.
D) the way in which separate folded monomeric protein subunits associate to form oligomeric proteins.
E) all are true.

Question

Quizplus · Accepted Answer

Tertiary structure refers to the three-dimensional folding of a single polypeptide chain, which is critical for the protein's function. This folding is determined by the interactions between amino acid side chains within the polypeptide chain, including hydrogen bonds, disulfide bonds, hydrophobic interactions, etc.

Option A is incorrect because this refers to the primary structure of a protein, which is simply the linear sequence of amino acids. Option C is incorrect because it describes the formation of secondary structure elements such as alpha helices or beta sheets, which are important components of tertiary structure but not sufficient to define it. Option D describes quaternary structure, which involves the association of multiple protein subunits, and is not necessary for all proteins to have a defined tertiary structure.

Tertiary Structure Is Defined As