While genes are said to provide the instructions, blueprints, programs, or recipes for protein synthesis, proteins themselves (which play structural and functional roles in the physiological activities of the cell), are commonly described as machines, motors, pumps, receptors, switches, messengers, recruiters, and cooperators that work together to carry out all the functions required of a living cell. Scientists employ these anthropomorphic and technomorphic metaphors to help themselves understand what proteins do and how they do it. As with the language of molecular genetics, there is often healthy debate among molecular biologists about the strengths and weaknesses of these metaphors for protein structure and function.