Viruses are considered to be nonliving particles, although they are still capable of evolving. They lack many of the defining characteristics of life. Viruses do, however, have genetic material(DNA or RNA),which is housed within a capsid and sometimes within an envelope. Viruses require a host cell to replicate and often utilize the host cell’s enzymes, ribosomes, and RNA molecules, ultimately killing the host cell after replication.
Virus: Tiny, nonliving particle that contains DNA but lacks other characteristics of living cells.
Virion: Individual virus particle.
Capsid: The protein coat that encloses the virus’s genetic material.
Latency: The dormant state of a virus.
Viruses lack many of the characteristics of living things. They are unable to self-reproduce or carry out metabolism. On a structural level, viruses lack organelles, a cytoplasm, and a cell membrane.
A virion is much smaller than a prokaryotic cell.
There are two parts of viral reproduction:
lytic cycle and lysogenic cycle.
In this cycle, the virus infects the host cell, replicates and forms new viruses using the host cell’s cellular machinery, and then ruptures, or lyses, the host cell, killing the host. Viruses that only undergo the lytic cycle are virulent.
The lysogenic cycle is the alternate cycle of viral infection. In the lysogenic cycle, the virus infects the host cell but lays dormant, or latent. All viruses that enter the lysogenic cycle will eventually enter the lytic cycle and kill their host cells.
Viruses cause many common diseases, such as chicken-pox, shingles, polio, hepatitis, and HIV.
Although viruses can be very hard to treat, one way society attempts to control the spread of disease is through vaccines. A vaccine exposes your body to non-infection variant of the viruses and allows your body to build up immunity to the virus.
Viruses also play an important role in cutting-edge science research.