Which of the Following Statements About Proteins is INCORRECT

Question

Which of the following statements about proteins is INCORRECT?
A) All proteins are made up of some combination of 20 essential amino acids.
B) Like nucleic acids, polypeptides have polarity.
C) A single polypeptide has primary, secondary, and tertiary structures.
D) $\alpha$-helix and $\beta$-pleated sheets do not require a specific sequence of amino acids to form.
E) Some proteins contain more than one polypeptide chain.

Accepted Answer

Not all proteins are made up of only the 20 essential amino acids; they are made up of 20 standard amino acids, which include both essential and non-essential amino acids.