The "permanent" wave that your local beauty parlor offers depends critically on rearrangements in the extensive disulfide bonds of keratin that give your hair its characteristic shape. to change the shape of your hair (that is, to give it a wave or curl), the beautician first treats your hair with a sulfhydryl reducing agent, then uses curlers or rollers to impose the desired artificial shape, and follows this by treatment with an oxidizing agent. part a what is the chemical basis of a permanent? drag the terms on the left to the appropriate blanks on the right to complete the sentences. peptide ionic disulfide amide cysteine tertiary alanine primary tyrosine hair proteins are first treated with a sulfhydryl reducing agent to break bonds and thereby destroy much of the natural structure and shape of the hair. after being set in the desired shape, the hair is treated with an oxidizing agent to allow the bonds to re-form between different groups, as determined by the positioning imposed by the curlers.