Viruses that infect bacterial cells are bacterial viruses are commonly known as bacteriophages. Bacteriophages attach to the bacterial cell wall, enter the cell, and replicate using the cell’s machinery. The new phage particles are then released from the cell after lysing it. T4 phage is a bacteriophage that can produce more than three hundred phages within 20 minutes of injecting its genetic material into the bacterial cell.
Archaeal viruses are another virus replicating within the archaea, organisms found in extreme environments. The viruses infecting archaeal cells can survive these extreme conditions and replicate within them. Archaeal viruses are composed of a viral envelope, a lipid membrane, a capsid, and genome material, which is mostly DNA but, in some cases, can be RNA. Some known archaeal viruses are Sulfolobus spindle-shaped viruses (SSVs), Acidianus Tailed Spindle Viruses (ATSV), Metallosphaera turreted icosahedral viruses, and Methanosarcina spherical viruses.