BIOL 1002 Chapter : Ch 19 Prokaryotes And Viruses
Document Summary
Diversity of prokaryotes and viruses chapter 19. In terms of abundance, prokaryotes rule as earth"s predominant form of life. Life on earth was solely prokaryotic for the first 1. 5 billion years. The prokaryotic domains (bacteria and archaea) were the first organisms and arose on earth (about. 3. 5 billion years ago): while only about 5000 prokaryotic species have been described, there may be as many. The thickness of a dime is about 1 millimeter (1000 micrometers). The two domains appear similar in many respects however they are different in some very basic ways: one main distinction between the bacteria and the archaea is that the cell walls of bacteria contain peptidoglycan (archaea do not) This bacterial cell wall is composed of peptidoglycan. Peptidoglycan is a complex of structural polysaccharides cross-linked by peptides. Locomotion: shape, pigments, nutrients required, staining properties. The cell wall of bacteria gives it the different types of characteristic shapes (see fig.
