The extra costs forprenatal care and complicated births among women whosmoke during pregnancy are more than $4 billion ayear. 1 Care for childhood illnesses resulting fromexposure to tobacco smoke costs nearly $8 billion a year.As a result, reducing parental smoking can producesubstantial economic benefits for society.
If the amine and carboxylic acid functional groups in amino acids join together to form amide bonds, a chain of amino acid units, called a peptide, is formed. A simple tetrapeptide structure is shown in the following diagram.
The peptide bonds that link amino acid residues in a polypeptide are formed in a condensation reaction between the acidic carboxyl group of one amino acid and the basic amino group of another amino acid. In the context of a peptide, the amide group (COâNH) is referred to as the peptide group.