Which of the following best reflects why viruses must use living cells to reproduce?

• A. Viruses lack the necessary cellular machinery for protein synthesis and energy production.
• B. Viruses require sunlight to activate their genetic material.
• C. Viruses are unable to survive outside of water.
• D. Viruses cannot bind to any molecules without a host cell.

Answer: (A)

Verified step by step guidance

1. Understand that viruses are acellular entities, meaning they do not have the structures typical of living cells, such as ribosomes or mitochondria.
2. Recognize that protein synthesis requires ribosomes and energy production requires metabolic pathways, both of which are absent in viruses.
3. Identify that because viruses lack these essential cellular components, they cannot independently produce proteins or generate energy needed for replication.
4. Conclude that viruses must infect living host cells to hijack their cellular machinery to replicate their genetic material and produce viral proteins.
5. Evaluate the other options and see that they do not accurately explain the fundamental reason why viruses depend on host cells for reproduction.