List the four properties that define a virus. What is a virion?

Verified step by step guidance

1. Identify the four key properties that define a virus, which typically include: (1) being acellular, meaning viruses are not made of cells; (2) containing genetic material, either DNA or RNA, but not both; (3) requiring a host cell to replicate, as viruses cannot reproduce independently; and (4) having a protein coat called a capsid that encases the genetic material.
2. Explain that viruses lack metabolic processes and cannot generate energy or synthesize proteins on their own, which distinguishes them from living cells.
3. Define a virion as the complete, infectious form of a virus outside a host cell, consisting of the viral genome enclosed within the protective protein coat (capsid), and sometimes surrounded by an envelope derived from the host cell membrane.
4. Clarify that the virion is the extracellular particle that can transfer the viral genome from one host cell to another, enabling infection.
5. Summarize by linking the properties of viruses to the structure and function of the virion, emphasizing its role in the viral life cycle.

Key Concepts

Properties that Define a Virus

Viruses are defined by four main properties: they contain genetic material (DNA or RNA), are surrounded by a protein coat called a capsid, lack cellular structure, and require a host cell to replicate. These features distinguish viruses from living cells and other microorganisms.

Genetic Material in Viruses

Viruses carry either DNA or RNA as their genetic material, but never both. This nucleic acid encodes the information necessary for viral replication and infection, and its type is a key factor in virus classification.

Virion Definition

A virion is the complete, infectious form of a virus outside a host cell. It consists of the viral genome enclosed within the protective protein coat (capsid), and sometimes an outer lipid envelope, enabling the virus to survive and transmit between hosts.