Hair is Surprisingly Strong: A single hair can support a load of about 100 grams without breaking. You could even spin rope out of hair!
The keratin protein of the cortex is responsible for this unusual strength. The long keratin molecules in the cortex are compressed to form a regular structure, which is not only strong but also flexible.
Proteins are made up of long chains of amino acids. Each chain takes up a helical or coiled form, rather like a long spring, or the cable of a telephone handset.
Most protein chains are made up of various mixtures of the same 20 or so amino acids. Keratin is unique in that its chains contain high concentrations of a particular amino acid called cystine. The proteins in the matrix of the hair contain the highest levels of cystine.
Every cystine unit contains two cysteine amino acids in different chains which have come to lie near to each other and are linked together by two sulphur atoms, forming a very strong chemical bond known as a disulphide linkage. Many disulphide bonds form down the length of the keratin chains, joining them together like the rungs of a ladder.
The disulphide bond is one of the strongest bonds known anywhere in nature. This cross-linking by disulphide linkages between the keratin chains accounts for much of the strength of hair.
The keratin protein of the cortex is responsible for this unusual strength. The long keratin molecules in the cortex are compressed to form a regular structure, which is not only strong but also flexible.
Proteins are made up of long chains of amino acids. Each chain takes up a helical or coiled form, rather like a long spring, or the cable of a telephone handset.
Most protein chains are made up of various mixtures of the same 20 or so amino acids. Keratin is unique in that its chains contain high concentrations of a particular amino acid called cystine. The proteins in the matrix of the hair contain the highest levels of cystine.
Every cystine unit contains two cysteine amino acids in different chains which have come to lie near to each other and are linked together by two sulphur atoms, forming a very strong chemical bond known as a disulphide linkage. Many disulphide bonds form down the length of the keratin chains, joining them together like the rungs of a ladder.
The disulphide bond is one of the strongest bonds known anywhere in nature. This cross-linking by disulphide linkages between the keratin chains accounts for much of the strength of hair.