One difference between viruses and bacteria is that a virus can live and reproduce only by penetrating other cells and becoming part of them, while bacteria can live and reproduce on their own. Which statement is true?

One difference between viruses and bacteria is that a virus can live and reproduce only by penetrating other cells and becoming part of them, while bacteria can live and reproduce on their own. Which statement is true?

• A. Viruses require host cells to reproduce; bacteria can reproduce on their own.
• B. Virus can reproduce on their own; bacteria require host cells.
• C. Both viruses and bacteria require host cells to reproduce.
• D. Neither viruses nor bacteria can reproduce outside a host.

Answer: (A)

Viruses cannot reproduce on their own because they lack the cellular machinery needed to make proteins or generate energy. They exist as inert particles outside a cell, and to replicate they must infect a living cell, hijack that cell’s machinery to copy viral genes and synthesize viral proteins, assemble new virus particles, and then release them. This dependence on a host cell is why viruses are considered obligate intracellular parasites. Bacteria, in contrast, are living cells with their own ribosomes, metabolism, and cellular machinery. With the right nutrients and conditions, they can grow and divide independently—typically by binary fission—without needing a host cell. So the statement that viruses require host cells to reproduce while bacteria can reproduce on their own correctly distinguishes their fundamental lifestyles.

Viruses cannot reproduce on their own because they lack the cellular machinery needed to make proteins or generate energy. They exist as inert particles outside a cell, and to replicate they must infect a living cell, hijack that cell’s machinery to copy viral genes and synthesize viral proteins, assemble new virus particles, and then release them. This dependence on a host cell is why viruses are considered obligate intracellular parasites.

Bacteria, in contrast, are living cells with their own ribosomes, metabolism, and cellular machinery. With the right nutrients and conditions, they can grow and divide independently—typically by binary fission—without needing a host cell.

So the statement that viruses require host cells to reproduce while bacteria can reproduce on their own correctly distinguishes their fundamental lifestyles.