BIOL-2420 Unit 3C Chapter 6: Acellular Pathogens

These flashcards cover key concepts related to acellular pathogens, specifically viruses, including their structure, replication, classification, and medical significance.

What is a virus?

An acellular infectious particle that infects various hosts, including plants, animals, bacteria, and archaea.

What distinguishes viruses from cellular pathogens?

Viruses are acellular, obligate intracellular parasites that cannot replicate without a host, unlike cellular pathogens.

Define virion.

A virus particle made up of nucleic acid (DNA or RNA) and a protective protein coat (capsid).

What are the main components of a virion?

Genome, capsid, capsomeres, envelope, and spikes.

What role do capsid proteins serve in viruses?

Capsid proteins protect the viral genome and help in attachment to host cells.

What are the two common methods of virion release from a host cell?

Budding for enveloped viruses and lysis for nonenveloped viruses.

What is the lytic cycle?

A viral reproduction cycle where the virus replicates and ultimately lyses (kills) the host cell.

Describe the lysogenic cycle.

A viral reproductive cycle where the virus integrates into the host chromosome and can remain dormant before entering the lytic cycle.

How do viruses differ in size relative to bacteria and eukaryotic cells?

Viruses are significantly smaller than most bacterial and eukaryotic cells, typically ranging from ~10 to 400 nm.

What is viral uncoating?

The process where enzymes dissolve the viral envelope and capsid to release the viral genome into the host cell's cytoplasm.

What does the term 'tropism' refer to in virology?

The ability of a virus to infect specific host cells or tissues.

What is the role of the envelope in enveloped viruses?

The envelope helps the virus enter host cells and evade the immune response.

What are inclusion bodies in the context of viral infections?

Intracellular structures formed by the accumulation of viral proteins within infected cells.

Give an example of a virus known to act as a teratogen.

Rubella virus, which can cause malformation in embryos.

What is a plaque in virology?

A clear area in a bacterial lawn formed by the lysis of bacteria by a bacteriophage.

How are viruses quantitated using the plaque assay?

The number of plaques formed is counted and multiplied by dilution factors to determine PFU/mL.

What are oncoviruses?

Viruses that can cause cancer by transforming normal cells into cancerous cells.

Name two methods viruses use to penetrate host cells.

Direct penetration for non-enveloped viruses and endocytosis for both enveloped and non-enveloped viruses.