One way to categorize viruses is how they reproduce. Retroviruses contain a strand or strands of vi...
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One way to categorize viruses is how they reproduce. Retroviruses contain a strand or strands of viral RNA as their genetic material and an enzyme called reverse transcriptase. After the virus infects a cell, this enzyme is used to make copies of viral DNA from viral RNA. Double strand copies of viral DNA are inserted into the nucleus of the host cell. Another viral enzyme, called integrase, inserts the viral DNA into the host cell DNA so that when the host cell reproduces its own DNA, the viral DNA is also reproduced. Through a process called transcription, the DNA sequence is used to reproduce an equivalent copy of viral RNA. These RNA strands are templates for making new copies of RNA and are also used for making viral proteins. The new virus particles are assembled, and bud and release from the host cell membrane.