A virus is about ten times smaller than a typical bacteria cell, and at least 100 times smaller than a typical eukaryotic cell.

A typical virus measures about 100 nm, ten times smaller than an average bacterium (~1 µm), which is at least ten times smaller than a regular plant or animal cell (~10–100 µm)

Key Points

• A virus is about ten times smaller than a typical bacteria cell, and at least 100 times smaller than a typical eukaryotic cell.

Key Terms

virus: a segment of DNA that can move to a different position within a genome

bacterium: able to be transposed (in any sense)

nm: nanometre or nanometer is a unit of length in the metric system, equal to one billionth of a metre

µm: micrometre is an SI derived unit of measure equalling 1×10⁻⁶ metre

eukaryotic cells: contain a nucleus that is enclosed by a plasma membrane.