This book has information about prokaryotes, prokaryotes are single-celled organisms that are the earliest and most primitive forms of life on earth. As organized in the Three Domain System, prokaryotes include bacteria and archaeans. Some prokaryotes, such as cyanobacteria, are photosynthetic organisms and are capable of photosynthesis. There are sections in this book that explain the role of membranes in transport, about bioenergetics of bacteria cells, Mycoplasma, immunology of bacteria membrane and receptors.