Question

how does the reproduction of a virus differ from the reproduction of a single-celled organism like amoeba?

Answer 1

Amoeba can exist free in nature with out a host support. They divide by binary fission.
Virus are not classified as organisms. They need a host synthetic machinery for replication, and won't survive long outside a living cell.

Answer 2

Viral reproduction is carried out in six stages: attachment, penetration, uncoating, viral genome replication, maturation and release. The virus attaches itself to a host, penetrates the organism to then uncoat the protective protein casing which houses the genetic information. Now inside the host cell, the viral genome can replicate and once it matures inside that first cell it is released into the host's organism so it can further replicate in other cells.

Amoebas for example carry out a type of asexual reproduction known as fission, in which one amoeba becomes two. The main difference between viruses and single-celled organisms is that the latter can replicate without the need of a host. This is why viruses are generally not classified as living things.