Question

Α-helices and β-sheets are examples of what level of protein structure?

1) Secondary structure
2) Tertiary structure
3) Quaternary structure
4) Primary structure

Answer 1

α-helices and β-sheets are secondary structures in proteins formed by hydrogen bonding in the peptide backbone and are a level above the primary amino acid sequence.

Step-by-step explanation:

α-helices and β-sheets are examples of the secondary structure of a protein. The protein structure is categorized into four different levels: primary structure, which is the sequence of amino acids; secondary structure, which includes α-helices and β-sheets and is maintained by hydrogen bonds; tertiary structure, which forms by further folding of the secondary structure; and quaternary structure, which involves interactions between two or more tertiary units.

The α-helix is a spiral shape formed by amino acids, while the β-sheet consists of alternating rows of amino acids in a side-by-side arrangement. Both of these structures are established due to the hydrogen bonding between carbonyl and amino groups in the peptide backbone of the polypeptide.