This document summarizes the replication processes of different types of viruses. It describes how DNA viruses like poxviruses replicate using their own DNA polymerase in the host cytoplasm. RNA viruses replicate through direct RNA-to-RNA copying. Retroviruses are unique in that they replicate indirectly through a DNA intermediate using reverse transcriptase. The replication of bacteriophages like T2, T4, and T6 involves five steps: attachment, penetration, biosynthesis of new viral components, maturation of assembled virions, and release through cell lysis.