Viral Structure, Bacteriophage Dynamics, and Animal Virus Infection Cycles

Comprehensive vocabulary flashcards covering viral structure, capsid architectures, bacteriophage lytic and lysogenic replication cycles, transduction, and animal virus infection cycles.

Virion

A single, complete, and technically correct term for an individual viral particle consisting of nucleic acid enclosed in a protein shell.

Capsid

The protein shell that encloses, protects, and carries the viral nucleic acid genome.

Helical Capsid

A spiral-shaped protein capsid that effectively forms a tight tube enclosing the viral nucleic acid inside.

Icosahedral Capsid

A 20-sided, hollow viral protein shell where each face is an equilateral triangle enclosing the nucleic acid.

Complex Capsid

A viral capsid structure combining multiple shapes, characterized by an icosahedral head containing the nucleic acid and a helical tail.

Envelope

A phospholipid bilayer surrounding the capsid of certain viruses, derived directly from the host cell's plasma membrane upon exit.

Naked Virus

A virus that lacks a surrounding phospholipid bilayer envelope, leaving only the capsid enclosing the genome.

Spikes

Protein, carbohydrate, or glycoprotein structures that attach to the capsid and project outwards (or through the envelope) to bind host cell receptors.

Host Range

The spectrum of organisms or specific host cell types that a particular virus is capable of binding and infecting.

Bacteriophage

A virus whose host range is restricted to bacterial species.

Lysozyme

An enzyme carried and synthesized by bacteriophages that degrades bacterial peptidoglycan during entry and exit.

Eclipse

The period immediately following entry during which intact, infectious virions cannot be detected because the nucleic acid is separated from the capsid.

Biosynthesis

The infection stage where the host bacterial chromosome is degraded and cellular machinery is hijacked to produce copies of viral nucleic acids and viral proteins.

Assembly (Maturation)

The lifecycle stage in which synthesized viral components are put together from individual molecules to construct complete new virions.

Lytic Cycle

A viral infection cycle that proceeds continuously through biosynthesis, assembly, and release, culminating in the lysis and death of the host cell.

Lysogeny

A bacteriophage cycle of infection where the viral DNA incorporates into the bacterial host chromosome rather than immediately destroying the cell.

Prophage

The dormant sequence of bacteriophage DNA that has integrated directly into the circular chromosome of a host bacterium.

Lysogenic Conversion

A change in the bacterial host's phenotype resulting from the expression of new genes introduced by an integrated prophage.

Specialized Transduction

Horizontal gene transfer occurring when an imprecise prophage excision takes flanking bacterial DNA and packages it into virions to transfer to a subsequent host.

Enterohemorrhagic E. coli

A pathogenic bacterial strain causing intestinal bleeding that acquired its Shiga toxin gene via specialized transduction.

Uncoating (Unsheathing)

An essential extra step in animal virus infection during which the viral nucleic acid escapes from the capsid and any surrounding membrane bubbles into the cytoplasm.

Provirus

Animal viral DNA that integrates into a host animal chromosome during a latent infection cycle.

Latent Cycle

An animal virus infection pathway where viral DNA inserts into a host cell chromosome as a provirus, remaining inactive until a trigger initiates excision and lytic replication.

Herpes Simplex Virus

A DNA virus causing cold sores that undergoes latent infections by hiding as proviruses in a small percentage of host cells between outbreaks.