Cytoplasm. The cytoplasm is the part of the cell which does all the work. Different cells do different jobs, however whatever the job is it will require energy in the form of a chemical called ATP. This energy containing chemical is produced by tiny organelles in the cell called mitochondria. Muscle cells contain two very special chemicals called actin and myosin.
Definition of TREPHINATION. : an act or instance of perforating the skull with a surgical instrument. ADVERTISEMENT.efinition of TREPHINATION. : an act or instance of perforating the skull with a surgical instrument. ADVERTISEMENT.
1. An involuntary trembling, sometimes an effect of paralysis, but usually caused by terror or fear; quaking; quivering. 2. Hence, a state of terror or alarm; fear; confusion; fright; as, the men were in great trepidation. 3. (Anc. Astron.) A libration of the starry sphere in the Ptolemaic system; a motion ascribed to the firmament, to account for certain small changes in the position of the ecliptic and of the stars.