Pieces of genetic material surrounded by a protein coat are called what?

• A. Bacteria
• B. Prions
• C. Endospores
• D. Viruses

Answer: (D)

The key idea here is what a virus actually is: a tiny package of genetic material—either DNA or RNA—wrapped in a protective protein shell called a capsid (and sometimes surrounded by a lipid envelope). This structure distinguishes viruses from other microscopic entities. They are not cells and cannot carry out metabolism or reproduce on their own; they must invade a host cell and use that cell’s machinery to make more viruses. That’s why “pieces of genetic material surrounded by a protein coat” best describes viruses.

In contrast, bacteria are full-fledged cells with their own cellular machinery; prions are infectious proteins that lack nucleic acid, so they don’t carry genetic material inside a protective coat; and endospores are dormant, highly resistant forms of bacteria, not simply a naked genome wrapped in protein.