A dipeptide is formed when two amino acids are joined together

A poly peptide is formed when more than 2 amino acids join together.

Amino acids have the same general structure: contain a carboxyl group connoted to an amine group. All living things are made from the same 20 Amio acids.

A polypeptide is formed when amino acids are joined together in a condensation reaction. A molecule of water is also released in the process and results in the formation of a peptide bond.

The primary structure is simply the sequence of amino acids in the polypeptide chain.

The secondary structure consists of Hydrogen bonds and result in the formation of beta pleated sheets and alpha helixes.

this consists of ionic bonds , disulphide bridges as well as hydrophilic and hydrophobic interactions.

The quaternary structure consists of several polypeptide chains which are bonded together. This is also the 3d structure of the protein.

Enzymes consist of a roughly spherical shape and are soluble due to their role as a matabolite.

Antibodies are involved in the immune response and theya re made of a light and heavy polypeptide chain. They are unique as the amino acid sequence can vary.

Transport proteins are found in the form of channel proteins etc. These are present in the cell membrane and they contain an hydrophobic and hydrophilic part of amino acids. these fold up to form channels which allow for the transportation of molecules across

Structural proteins are forund in the form of collegen wwhich contains long polypeptide chains which lie paralell to each other in cross links.

Add two drops of alkaline sodium hydroxide to the solution and then add some cupper 2 sulphate. the positive test is if the solution turns purple.