Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level. Knowledge of the molecular basis of cell structure, cell function and cell interaction is fundamental to an understanding of whole organisms, since the properties of organisms are dependent upon the properties of their constituent cells. Cell biology is the core course the students who are trained in a programme of medical science must handle very well. Cell biology reflects the great and distinguished advances of life science in recent century. Cell biology describes cell structures and functions, and the mechanisms, principles, or regulations of every life event and how to use cell as the essential platform to study them. Cell biology courses now form a foundation for many subsequent specializations in areas outside cell biology. We therefore cover molecular genetics, metabolic pathways and electrophysiology in sufficient detail to make Cell Biology a suitable course book for first year medical students who will later specialize in genetics, biochemistry, pharmacology or physiology