Viruses, Viroids, and Prions

Flashcards on Viruses, Viroids, and Prions

Virus

Latin for poison; obligatory intracellular parasites containing DNA or RNA and a protein coat (capsid).

Capsid

The protein coat of a virus, made up of capsomeres.

Obligatory intracellular parasites

Viruses that require a host cell to replicate.

Host range

Determined by specific host attachment sites and cellular factors.

Viridae

Family names of viruses end in this suffix.

Viral species

A group of viruses sharing the same genetic information and ecological niche (host).

Plaques (viruses)

Formed by bacteriophages on a lawn of bacteria, used for viral cultivation.

Cytopathic effects

Visible effects of viral infection on a cell.

Serological tests

Detect antibodies against viruses in a patient.

Lytic cycle

Phage causes lysis and death of host cell

Lysogenic cycle

Phage DNA incorporated in host DNA resulting in a prophage.

Prophage

Phage DNA that is incorporated into the host DNA.

Oncogene

A gene that can transform a normal cell into a cancerous cell when activated.

Latent viral infection

Virus remains in asymptomatic host cell for long periods.

Persistent viral infection

Disease processes occurs over a long period; generally is fatal.

Prion

Small proteinaceous infectious particles that are inherited and transmissible.

Spongiform encephalopathies

Diseases caused by prions, leading to characteristic sponge-like lesions in the brain.

PrPC

Normal cellular prion protein, found on the cell surface.

PrPSc

Scrapie protein; accumulates in brain cells, forming plaques.