Hair is curly or straight, depending upon the number of disulfide bonds between hair proteins found in the hair shaft.
The greater the number of links, the curlier the
hair, and the fewer the number of links, the straighter the hair.
Hair is primarily composed of keratin, a protein, which grows from a sac called
the follicle. Cells in the hair follicle generate keratin, and various other
proteins, which become a part of the hair shaft.
These...
