What are viruses?

What are viruses?

• A. Multicellular organisms
• B. Ultramicroscopic infectious agents that contain DNA or RNA
• C. Bacteria only
• D. Prions

Answer: (B)

Viruses are ultramicroscopic infectious particles that carry genetic material in the form of DNA or RNA and are enclosed in a protein coat. They aren’t cells and can’t carry out metabolism or reproduce on their own; they must infect a living cell and hijack that cell’s machinery to make new virus particles. That’s why they’re smaller than bacteria and rely on a host to replicate. The other descriptions don’t fit: multicellular organisms are made of many cells; bacteria are cellular organisms that can grow and reproduce on their own; prions are infectious proteins with no nucleic acid.

Viruses are ultramicroscopic infectious particles that carry genetic material in the form of DNA or RNA and are enclosed in a protein coat. They aren’t cells and can’t carry out metabolism or reproduce on their own; they must infect a living cell and hijack that cell’s machinery to make new virus particles. That’s why they’re smaller than bacteria and rely on a host to replicate. The other descriptions don’t fit: multicellular organisms are made of many cells; bacteria are cellular organisms that can grow and reproduce on their own; prions are infectious proteins with no nucleic acid.