Virion properties: which statement is NOT true about virions (complete virus particles)?

Introduction / Context: A virion is the complete, infectious form of a virus outside a host cell, typically composed of nucleic acid (DNA or RNA), a protein capsid, and sometimes an envelope. Knowing what virions can and cannot do clarifies viral life cycles and the distinction between viruses and cellular life.

Given Data / Assumptions:

• Virions carry either DNA or RNA (never both simultaneously as their genetic material).
• Virions are metabolically inert outside host cells.
• Replication requires host cellular machinery after entry and uncoating.

Concept / Approach: The key question is to find the statement that is not true. Virions can be found extracellularly; they indeed exist as particles outside the cell while seeking new hosts. Some viruses contain DNA; others contain RNA—either possibility is true, depending on the virus family. However, virions do not reproduce independently: they lack ribosomes, energy metabolism, and the enzymatic systems necessary for autonomous replication.

Step-by-Step Solution:

Verification / Alternative check: Standard virology texts characterize virions as obligate intracellular parasites for replication.

Why Other Options Are Wrong:

• Contain DNA / Contain RNA: Each is correct in the appropriate viral lineage.
• Are extracellular: Correct description of the virion state.

Common Pitfalls: Thinking “contain DNA” and “contain RNA” are mutually exclusive in the answer key; both can be true statements broadly across viruses, but only one applies to any given species.

Final Answer: Reproduce independently