Answer:
When the virus enters a living cell (a human cell, if the virus infects humans, or a bacterial cell, if the virus infects bacteria) it reprograms that cell and turns the cell into a virus factory. Adaptive Immunity: All organisms have different types of immunity to protect themselves against infection.
While both can cause disease, viruses are not living organisms, whereas bacteria are. Viruses are only "active" within host cells which they need to reproduce, while bacteria are single-celled organisms that produce their own energy and can reproduce on their own.
As you might think, bacterial infections are caused by bacteria, and viral infections are caused by viruses. Perhaps the most important distinction between bacteria and viruses is that antibiotic drugs usually kill bacteria, but they aren't effective against viruses.
Some bacteria help to digest food, destroy disease-causing cells, and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt and cheese. But infectious bacteria can make you ill. They reproduce quickly in your body.