Virus and red blood cells. Computer artwork of a virus under a magnifying glass surrounded by red blood cells. Viruses consist of a small core of genetic material, either DNA (deoxyribonucleic acid) or RNA (ribonucleic acid), surrounded by a protein coat, or capsid. The capsid itself may be surrounded by a glycoprotein envelope. Viruses are primitive organisms that lack the ability to reproduce independently of a host cell.