List and describe the structural components of viruses?

Infectious particles consisting of nucleic acid encased in a protein coat and, in some cases, a membranous envelope. The smallest viruses are only 20 nm in diameter. The genome of viruses may consist of double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA, depending on the kind of virus. Lack the enzymes for metabolism and the ribosomes for protein synthesis. Identify host cell (needed for reproduction) by a lock and key type system of outer proteins.