ABSTRACT
This chapter is about cells, the fundamental units of life on Earth. As you will see, the molecular biology of even the simplest of cells is, paradoxically, complex. In the following sections, we will review the anatomical features, the molecular biology, and the physiological properties of cells belonging to the three domains of life: the Prokaryotes, the Archaeans, and the Eukaryotes. One common feature of all life is that the double-stranded DNA (dsDNA) molecule is used to store the information required for self-reproduction (of the cell and the organism in which it resides), as well as the information required to do metabolism, maintain homeostasis (“molecular housekeeping”), and execute the cell’s function. DNA codes protein and RNA synthesis, and sequences developmental events, including programmed cell death (apoptosis). Another common feature of all cells is their cell membranes, described in the following section. Cell membranes have a common architecture, but molecular details vary between the domains and kingdoms of life.
