Drag each label into the appropriate bin depending on whether it applies to primary, secondary, tertiary, or quaternary structure.

Proteins have a complex structure that can be described at the four levels of primary, secondary, tertiary, and quaternary structure (click on the figure on the left). Because proteins are assembled using the instructions coded in DNA, mutations in DNA often affect protein structure. A point mutation changes a single nucleotide in DNA, either by substituting one nucleotide for another or through the insertion or deletion of a single nucleotide (click on the figure on the right). Point mutations can have a range of effects on protein structure--some have no effect at all, whereas others disrupt protein structure completely.