Virus Basics and Structure

Viruses are not cells, they lack a cytoplasmic membrane, cytoplasm, ribosomes, and are generally smaller than cells.

Viruses are obligate intracellular parasites, meaning they cannot replicate outside of a living host cell.

The genetic material of a virus, which can be DNA or RNA, either single or double-stranded, and linear or circular.

A protective protein coat surrounding the viral genome, often either polyhedral or helical in shape.

A lipid layer surrounding the capsid of some viruses, not a true cell membrane.

Viruses with a polyhedral capsid, which means the shape is composed of many sides.

Viruses with a helical capsid, which means the shape is similar to a spiral or helix.

The structural units that make up the capsid of a virus.

A virus with a capsid composed of many symmetrical subunits arranged in a polyhedral shape, often resembling an icosahedron.

A virus lacking an outer lipid envelope, which is a protective membrane derived from the host cell.

A virus with an outer lipid envelope that encapsulates the capsid, acquired from the host cell membrane.

Viruses lacking a distinct icosahedral or helical symmetry and often having complex structures, like a head and tail.

A virus that replicates within a host cell, causing the cell to burst and release new viral particles, leading to cell lysis.

The attachment of a virus to its host cell.

The entry of a virus into its host cell.

The process of viral replication where the viral genome is transcribed and translated to produce viral proteins. This process also involves the replication of the viral genome itself.

Double-stranded DNA viruses must first be transcribed into mRNA in the host cytoplasm before viral proteins can be translated.

Viral proteins are translated from viral mRNA using the host cell's ribosomes and tRNA.

The process of replicating the viral genome. This can involve different mechanisms depending on the type of viral genome. For example, viruses with dsDNA genomes need to replicate their DNA using host enzymes.

The coding strand of single-stranded RNA viruses is directly translated into viral protein.

Single-stranded RNA viruses need to package an RNA-dependent RNA polymerase (RNA replicase) to replicate their genome.

Single-stranded DNA viruses need an origin of replication to make more copies of their genome.

Single-stranded DNA viruses must first be transcribed into mRNA in the host cytoplasm before viral proteins can be translated.