Angry virus - white on dark T-Shirt

A virus is a microscopic parasite that can infect living organisms and cause disease. It can make copies of itself inside another organism's cells. Viruses consist of nucleic acid and a protein coat. Usually the nucleic acid is RNA; sometimes it is DNA. Viruses are able to cause many types of diseases, such as polio, ebola and hepatitis. Virology is the study of viruses. Viruses reproduce by getting their nucleic acid strand into a prokaryote or eukaryote (cell). The RNA or DNA strand then takes over the cell machinery to reproduce copies of itself and the protein coat. The cell then bursts open, spreading the newly created viruses. All viruses reproduce this way, and there are no free-living viruses.