Question

part e
large proteins, like dna polymerase and hemoglobin, are often composed of several polypeptides that are linked together. the ____ level of protein structure describes how the polypeptides are joined to create a larger complex.
first
second
third
fourth

Explanation:

Protein structure has four levels. The primary structure is the linear sequence of amino - acids. The secondary structure is formed by local folding (e.g., alpha - helices and beta - sheets). The tertiary structure is the three - dimensional structure of a single polypeptide chain. The quaternary structure describes how multiple polypeptide chains come together to form a multi - subunit complex. Since the question is about how multiple polypeptides are joined to create a larger complex, it refers to the quaternary (fourth) level of protein structure.

Answer:

D. fourth