Structure of viruses Most viruses are too small to be seen under light microscope. All viruses consists of an RNA or DNA core genome surrounded by a protein coat capsid. The combined viral genome and capsid is called the nucleocapsid capsid Envelope Consid Card Naked virus Enveloped vrus• Most viruses are too small to be seen under light microscope. • All viruses consists of an RNA or DNA core genome surrounded by a protein coat capsid. • The combined viral genome and capsid is called the nucleocapsid. Structure of viruses