What Level of Protein Structure is Composed of

Question

What level of protein structure is composed of $\alpha$ helices, $\beta$ sheets, and turns?
A) primary
B) secondary
C) tertiary
D) quaternary
E) both secondary and tertiary

Accepted Answer

The secondary structure of proteins is characterized by the formation of $\alpha$ helices and $\beta$ sheets, which are stabilized by hydrogen bonds.

What level of protein structure is composed of α\alphaα helices, β\betaβ sheets, and turns?

What level of protein structure is composed of $\alpha$ helices, $\beta$ sheets, and turns?