Which statement about viruses is true?

Which statement about viruses is true?

• A. Viruses require a host to reproduce
• B. Viruses are larger than bacteria
• C. All viruses cause disease in humans
• D. Antibiotics can treat viral infections

Answer: (A)

Viruses are obligate intracellular parasites: they cannot carry out metabolism or reproduce on their own. They lack the cellular machinery needed to copy their genetic material or synthesize viral proteins, so they must infect a living cell and hijack that cell’s ribosomes, enzymes, and energy to make new copies of the virus. That dependence on a host cell is why the statement is true: viruses reproduce only inside a host. Context helps: viruses are typically much smaller than bacteria, and antibiotics target bacteria, not viruses, so they don’t treat viral infections. There are antiviral drugs that target specific steps in the viral life cycle, but they’re not the same as antibiotics. Also, not all viruses cause disease in humans; some infections are asymptomatic or resolved by the immune system.

Viruses are obligate intracellular parasites: they cannot carry out metabolism or reproduce on their own. They lack the cellular machinery needed to copy their genetic material or synthesize viral proteins, so they must infect a living cell and hijack that cell’s ribosomes, enzymes, and energy to make new copies of the virus. That dependence on a host cell is why the statement is true: viruses reproduce only inside a host. Context helps: viruses are typically much smaller than bacteria, and antibiotics target bacteria, not viruses, so they don’t treat viral infections. There are antiviral drugs that target specific steps in the viral life cycle, but they’re not the same as antibiotics. Also, not all viruses cause disease in humans; some infections are asymptomatic or resolved by the immune system.