Proteins, from the Greek proteios, meaning first, are a class of organic compounds which are present in and vital to every living cell. In the form of skin, hair, callus, cartilage, muscles, tendons and ligaments, proteins hold together, protect, and provide structure to the body of a multi-celled organism. In the form of enzymes, hormones, antibodies, and globulins, they catalyze, regulate, and protect the body chemistry.
Definition of long division for Students. : division in arithmetic that involves several steps that are written out.
Overview of the cell division cycle. The cell division cycle is a series of events that take place in a cell leading to its division and duplication. In unicellular species (no cell nucleus) such as bacteria, cell division occurs by a process called binary fission and produces a new organism.