The primary structure of a protein is:

Answer and explanation

Correct answer: A. The sequence of amino acids in the polypeptide chain

  1. Step 1: Primary structure is the order of amino acids determined by the gene. Answer: The sequence of amino acids in the polypeptide chain. Why not the others: an alpha helix is secondary structure; three-dimensional folding is tertiary; joining of chains is quaternary structure.

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