Final answer:
The perm solution used in alkaline perms breaks or reduces the disulfide bonds in the hair, allowing it to be reshaped and setting the new form with an oxidizing agent.
Step-by-step explanation:
In alkaline perms, the perm solution chemically breaks or reduces the disulfide bonds in the hair. These are strong covalent bonds found between cysteine molecules in hair proteins, particularly keratin.
The process involves the use of a basic reducing substance, like ammonium thioglycolate, to disrupt the disulfide links, allowing the hair to take on a new shape around rollers or curlers.
Afterward, an oxidizing agent (commonly hydrogen peroxide) is applied to re-form these disulfide bonds, therefore setting the hair into its new form. The remade disulfide bonds will maintain the hair's new shape until it grows out or is otherwise treated.