Question

changes in environment, such as increased heat and ph changes, can denature a protein. which levels of protein structure are affected when a protein is denatured? choose the single best answer from the list below. only primary. tertiary and quaternary. primary and secondary. secondary, tertiary, and quaternary. primary, secondary, tertiary, and quaternary.

Explanation:

Protein denaturation affects secondary, tertiary, and quaternary structures. The primary structure, which is the amino - acid sequence, remains intact during denaturation as it is held by covalent peptide bonds. Secondary, tertiary, and quaternary structures are held by non - covalent interactions like hydrogen bonds, van der Waals forces, and disulfide bridges (in tertiary and quaternary for multi - subunit proteins), which are disrupted by changes in heat and pH.

Answer:

D. Secondary, tertiary, and quaternary