BIOL 230: Introduction to Viruses, Viroids, and Prions

Flashcards of vocabulary terms and definitions related to viruses.

Pasteur

Proposed that rabies was caused by a “living thing” smaller than a bacterium - he proposed the term “virus” which is Latin for poison.

Viruses

Requires an electron microscope to be visualized.

Poliovirus

A virus that is 30 nm in size.

Smallpox virus

A virus that is 200 nm x 300 nm in size.

Tobacco mosaic virus

A virus that is 15 nm x 300 nm in size

Bacteriophage T4

A virus that is 50 nm x 225 nm

Viruses

Considered obligate intracellular parasites.

Viruses

acellular and cannot synthesize protein.

Viral Nucleic Acid

Either DNA or RNA (never both).

Capsid

Protein coat.

Viruses

Multiply by taking over the machinery of the host cell and redirecting it to make new viruses.

Viruses

Cannot exist independent of host cells

Naked Virus

All viruses have at least these components: Nucleic acid, Protein, Capsid.

Enveloped Virus

Formed by budding out of the host cell membranes in some viruses.

Spikes

Provide specificity of attachment to host cell receptors, and therefore determines the host range- what organisms it can infect

Capsids

The protein coats of a virus

Capsomers

A subunit of the capsid.

Shapes

Broad classifications of Capsids (helical, icosahedral (polyhedral), or complex).

Helical Capsids

Capsids that are arranged into hollow disks.

Icosahedral (polyhedral) Capsids

Capsids that have 20 sides with 12 corners.

Complex Capsids

Capsids that have other features.

Capsid and Envelope

Protects the genomic core of the virus.

Envelopes

Formed from the host cell membranes.

Hemagglutinin

Allows them to attach to RBC.

Neuraminidase

Allows mature virons to leave cell.

Adsorption

the virus attaches to the host cell using its spikes- also called ‘docking’.

Penetration

the virus is brought into the cell by endocytosis (cell membrane).

Uncoating

the viral capsid (and envelope) are removed and nucleic acid is freed.

Synthesis, Replication and Protein Production

The virus directs the host cell to make more viral components- nucleic acid, capsid proteins, and spikes

Assembly

the viral components are assembled into new virus particles (virions).

Release

the virus leaves the cell as it ruptures or buds out of the cell membrane

CPE

Animal viruses can damage or kill the host cells leading to tissue damage or disease. Include: Inclusion bodies, Syncytia.

Syncytia

Respiratory syncitial virus

Inclusion bodies

HCMV

Dermatotropic

Virus infects skin, mucous membranes.

Pneumotropic

Virus infects respiratory tract.

Neurotropic

Virus infects the central nervous system.

Viscerotropic

Virus infects vicera (internal organs) liver, glands, intestines

Immunological

Virus infects cells of the immune system.