Lymphedema (lymphoedema in British English), also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then the bloodstream.ymphedema (lymphoedema in British English), also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then the bloodstream.
1 A polypeptide is a single linear chain of many amino acids, held together by amide bonds. 2  A protein is one or more polypeptide (more than about 50 amino acids long).  An oligopeptide consists of only a few amino acids (between two and twenty).
Generally speaking, a link of amino acids greater than 50 is considered a polypeptide. Groupings of polypeptides make proteins in various forms like primary, secondary, teritiary and quaternary structures. So the most basic subunit of the protein is the amino acid. Carbohydrate subunits are sugars.