Which of the following is not true about Virion ?

Question

Accepted Answer

The correct option is 1: Intracellular

The correct option is Intracellular because it is the statement that is **NOT true** regarding a virion. The term **virion** is used by virologists to specifically describe the complete, fully assembled, and infectious virus particle that exists **outside** the host cell. This particle is structurally stable and essentially metabolically inert, functioning as a vehicle for the viral genome. Its entire purpose is to survive the harsh environment and transport the genetic material to a new, susceptible host cell. Therefore, by definition, the virion represents the **extracellular** phase of the virus life cycle. Once this particle enters a host cell, it uncoats, and the viral genome begins replication and expression, a stage referred to as the intracellular, or *active*, virus. Thus, the term 'virion' and the description 'intracellular' are mutually exclusive for the same entity at the same moment.

The incorrect option is 2: Extracellular

This option is a correct description of a virion, which is why it is the incorrect choice for the question asking for a *false* statement. As established, the virion is the infectious agent in its fully formed, transportable state, waiting to encounter and infect a new cell. It is the stable, dormant particle of the virus existing in the environment or moving through the body fluids, which is precisely the meaning of **Extracellular**. This phase is critical for the virus's spread from one host to another, representing a non-replicating state.

The incorrect option is 3: Acellular

This option is a correct description of a virion, confirming it as an incorrect answer choice. All viruses, including the virion particle, are fundamentally **Acellular**. This means they do not possess the complex cellular structure, such as a nucleus, cytoplasm, organelles like ribosomes, or a plasma membrane, which are characteristic of all living cells (prokaryotic and eukaryotic). Instead, a virion is composed primarily of a nucleic acid genome (DNA or RNA) enclosed in a protein coat (capsid), and sometimes a lipid envelope. Because they lack cellular machinery, they are obligate intracellular parasites, entirely dependent on a host cell for reproduction and metabolism.

The incorrect option is 4: Crystalizable

This statement is a correct and historic fact about virions, rendering it an incorrect choice for the question. The property of being **Crystalizable** was famously demonstrated in 1935 by Wendell Stanley, who successfully crystallized the Tobacco Mosaic Virus (TMV) without destroying its infectivity. The ability to be crystallized is characteristic of simple, uniform chemical compounds or complex macromolecules, but not of true living organisms. This critical observation provided early evidence that viruses were uniquely positioned at the border of living and non-living matter. This distinctive property stems from the virion’s highly regular, symmetrical structure and chemical inertness in its extracellular state.