How do simple viruses differ from complex ones?

Simple viruses are nucleoproteins, that is, they consist of one nucleic acid DNA or RNA and several proteins that form a membrane around the nucleic acid. The protein coat of the virus is called a capsid. An example of such a virus is the tobacco mosaic virus. Its capsid contains one low molecular weight protein.
Complex viruses have an additional membrane – protein or lipoprotein. Sometimes in the outer shells of complex viruses, in addition to protein, carbohydrates are contained, for example, herpes and influenza viruses. Their outer shell is a fragment of the cytoplasmic membrane of the host cell.