There are a few differences! First of all viruses must have a living host to multiply in (like a person or animal’s cells) whereas most bacteria can grow on non-living surfaces…like your dirty breakfast bowl. Because of this viruses are sometimes termed “dead” – but this is not strictly true (it depends what you consider a life!!). So how do viruses grow and multiply? well they are basically just a capsule containing genetic information (DNA or RNA) and nothing else so they need the host’s cells to multiply!
Viruses infect us to use our stuff to make more of themselves!! They turn the cell’s genetic material from its normal function to producing more virus! Clever evilness!
Bacteria are different – they carry all the machinery needed for their growth and multiplication so they can survive on their own without a host.
So you can think of bacteria more as like little animals I guess where as viruses are just information in a coat that can’t do anything until it gets into a cell to take it over!