Are viruses living?
1 Answer
No. Viruses, while they have DNA or RNA, are not living. They are not made of cells, they do not grow or develop, they do not carry out metabolism, and they cannot reproduce themselves. The purpose of a virus is to inject its genetic material into a host cell, which then takes over the host cell's DNA. The host cell then uses the virus genetic material to manufacture virus parts and assemble them into new viruses. So the cell replicates the viruses and then after enough viruses have been replicated, the cell ruptures and dies, releasing the new viruses.
The smallest organism currently known is the microbacterium Mycoplasma genitalium . It is a parasitic species and can be transmitted sexually. It lives on the ciliated epithelial cells of the urinary and genital tracts in humans.The bacterial cell is slightly elongated somewhat like a vase, and measures 0.6-0.7 μm in length, 0.3-0.4 μm at the broadest region, and 0.06-0.07 μm at the tip. Sources: http://en.wikipedia.org/wiki/Mycoplasma_genitalium and http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131060/
