Hey,

Prokarotic cells which do not have nucleus, and is surrounded by membranes which does not even contains any structures inside them are termed as bacterial cells. They can be useful and harmful also in some contexts.

Viruses are parasitic in nature and are microscopic and smaller in size as compared to bacteria. They select a host and reproduce and grow inside the host. They dont have the capability of reproducing outside the host body.

I Hope this helps.

All the best!