When a disulfide linkage is formed, the compound containing this new linkage has been

            When a disulfide linkage is formed, the compound containing this new linkage has been oxidized.

                   Oxidation reaction is defined as,

i) Addition of Oxygen Atoms:

                                   When oxygen atom is added to any compound, then the compound is said to be oxidized and the reaction is known as oxidation reaction.

Example:

Oxidation of Alcohols into carboxylic acids:

                                   R---CH₂--OH         →         R---COOH

ii) Removal of Hydrogen Atoms:

                                                    When hydrogen atom(s) are removed from any compound, then the compound is said to be oxidized and the reaction is also called as oxidation reaction.

Example:

Formation of disulfide bond fro thiols:

                                 R--S-H  +  R--S-H      →       R---S--S---R

Disulfide bond is quite popular in protein chemistry where it is formed in cystine from cystein amino acids.

a) the particles of the chair are strongly held together.