ABSTRACT

Proteins are directly responsible for almost all of the metabolic processes that occur within a cell. Specialized proteins are used for the generation of structural elements in a cell or an entire organism. The elaborate structure of DNA in a cell, now referred to as its genome. is meant to record the structure of an organism's proteins, both to serve as a template for the construction of copies of those proteins and to pass that crucial information on to the next generation. The proteins encoded by a genome can be organized into larger structures that are used as cellular machinery for performing specific tasks in a cell, such as transcribing DNA into more protein (which requires several discrete proteinbased machines), transporting other molecules through membranes, or automatically repairing damage to cellular subsystems. When genetic material is passed from one generation to the next, it is also necessary to pass a complete working set of protein-based machinery for the reading of the DNA strands and performing all other necessary steps in cell metabolism.