| Virus injecting its genetic material into a bacterium.|
© Gary E. Kaiser
Viruses cannot reproduce or express their genes without the help of a living cell.
Once a virus has "infected" a cell, it will "marshal" the cell's ribosomes, enzymes and much of the cellular machinery to reproduce.
Viral reproduction produces many, many progeny, that when complete, leave the host cell to infect other cells in the organism.
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