What are the parts of a coronavirus?

Coronaviruses are a large family of viruses, some of which infect humans.

The coronavirus at the root of COVID-19 is the newest known member of this family. And like other coronaviruses that infect people, the new coronavirus causes respiratory disease, among other symptoms.

Illustrations by Hailee Perrett, Ward Lab, Scripps Research.

At their core, coronaviruses contain a genetic blueprint called RNA (beige), similar to DNA. The single-stranded RNA acts as a molecular message that enables production of proteins needed for other elements of the virus.

Bound to this string of RNA are nucleoproteins— (dark blue discs)—proteins that help give the virus its structure and enable it to replicate.

Encapsulating the RNA genome is the viral envelope (teal), which protects the virus when it is outside of a host cell. This outer envelope is made from a layer of lipids, a waxy barrier containing fat molecules. As well as protecting the precious genetic cargo, this layer anchors the different structural proteins needed by the virus to infect cells. Envelope proteins (dark blue dots) embedded in this layer aid the assembly of new virus particles once it has infected a cell.

The bulbous projections seen on the outside of the coronavirus are spike proteins (red-orange). This fringe of proteins gives the virus its crown-like appearance under the microscope, from which the Latin name corona is derived. The spike proteins act as grappling hooks that allow the virus to latch onto host cells and crack them open for infection. Like all viruses, coronaviruses are unable to thrive and reproduce outside of a living host.