* Amino acids bind to each other to make polypeptide chains via a condensation reaction, which involves the elimination of a water molecule for each bond formed.
We show two amino acids next to each other with the carboxylic acid group of the first amino acid next to the amino group of the second amino acid.
We encircle both the hydroxyl group of amino acid 1 and also one of the hydrogen atoms on the amino group of amino acid 2.
These molecules are being eliminated as H2O.
We show the two amino acids joined together with the carboxyl C from amino acid 1 single-bonded to the N from amino acid 2.