Final answer:
Proteins do not always go from primary to tertiary structure. The four levels of protein structure are primary, secondary, tertiary, and quaternary.
Step-by-step explanation:
Proteins do not always go from primary to tertiary structure. The four levels of protein structure are primary, secondary, tertiary, and quaternary. The primary structure refers to the sequence of amino acids in the polypeptide chain, while the secondary structure refers to the local folding patterns, such as alpha helices and beta sheets. The tertiary structure refers to the overall 3D folding of the protein, which is determined by interactions between the amino acid side chains. The quaternary structure describes the arrangement of multiple polypeptide chains in a protein complex.