Which of the Following Levels of Protein Structure is Correctly

Question

Which of the following levels of protein structure is correctly defined?
A) primary: interaction between subunits of a protein
B) secondary: hydrogen bond arrangement of polar R-groups
C) tertiary: three dimensional arrangement of all atoms in a single peptide
D) quaternary: order of amino acid residues in the peptide chain
E) none of the above are correct

Accepted Answer

The tertiary level of protein structure refers to the three-dimensional arrangement of all atoms in a single peptide, including interactions between R-groups and the peptide backbone.

Answer: E
 None of the other options are correctly defined. 
- A) primary structure refers to the linear sequence of amino acids in a protein
- B) secondary structure refers to the repeating structures formed by hydrogen bonding between backbone atoms, such as alpha-helices or beta-sheets
- D) quaternary structure refers to the arrangement of multiple subunits in a protein complex.