Some viruses have membranes, while others do not. The essential parts of a virus are genetic material such as DNA or RNA enclosed in a protein capsid. In viruses with just these components, no membrane is present. However, some viruses do have a membrane called an envelope, which can add an extra layer of protection for the genetic material inside. This envelope is often composed of the host cell’s membrane, but can include glycoproteins native to the virus.

As for prions, these are simply misfolded proteins, with no membrane present. It is also important to know that prions are several orders of magnitude smaller than viruses, and don’t contain any genetic material. Instead, prions spread by inducing a misfolded shape in formerly healthy proteins in a cell. Hope this helps!