Question

drag the labels onto the diagram to identify the structures of proteins.

Explanation:

1. Primary structure: Defined by the linear sequence of amino acids in a polypeptide chain, matching the "linear chain of amino acids" diagram element.
2. Secondary structure: Forms from hydrogen - bonding between backbone atoms, creating motifs like alpha - helices or beta - pleated sheets, as seen in the "alpha - helix" / "pleated sheet" elements.
3. Tertiary structure: The overall 3 - D fold of a single polypeptide, including interactions like disulfide bonds, hydrophobic interactions, etc. The single folded chain with a heme group (e.g., a single globin chain) represents this.
4. Quaternary structure: Arises from the association of multiple polypeptide subunits (e.g., hemoglobin’s four subunits) or the structure of fibrous proteins (e.g., keratin/collagen’s multi - chain organization).

Answer:

• Linear chain of amino acids: Primary structure
• Alpha - helix / Pleated sheet: Secondary structure
• Single folded polypeptide (with heme): Tertiary structure
• Multiple subunits (hemoglobin) or fibrous (keratin/collagen): Quaternary structure