7.3.3 Amino Acids (HT only)

Amino acids are organic compounds that contain two different functional groupsAny group of atoms in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition. within their molecular structure. These functional groups are an amino group (-NH₂) and a carboxyl group (-COOH). The amino group consists of a nitrogen atom bonded to two hydrogen atoms, while the carboxyl group consists of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group (-OH).

Amino acids can undergo a specific type of condensation polymerisation known as peptide bond formation. During this process, the amino group of one amino acid reacts with the carboxyl group of another amino acid, resulting in the formation of a peptide bond (-CONH-) and the release of a water molecule. This reaction can occur between any two amino acids, allowing for a wide variety of combinations.

The polymerisation of amino acids through peptide bond formation leads to the production of polypeptides. Polypeptides are chains of amino acids joined together by peptide bonds. The specific sequence and arrangement of amino acids within a polypeptide chain determine the structure and function of the resulting protein.

For example, glycine (H₂NCH₂COOH) is an amino acid that can polymerise to form a polypeptide chain. By linking multiple glycine molecules through peptide bonds, a polypeptide of various lengths can be created. Glycine (H₂NCH₂COOH) polymerises to produce the polypeptide:

In addition to glycine, there are numerous other amino acids with distinct side chains. These different amino acids can be combined in various sequences within a polypeptide chain, resulting in the synthesisCombining information from more than one text to show comparison. of diverse proteins. The specific arrangement of amino acids in a protein is crucial for its three-dimensional structure and function.