Virology Flashcards
(18 cards)
What are viruses?
Very small acellular infectious agents that are obligate intracellular parasites.
Why are viruses important to study?
They cause diseases, are useful in biotechnology, and are the most abundant biological entities on Earth.
What are the main structural components of a virus?
Genetic material, capsid, nucleocapsid, envelope, and spike proteins.
What are the main types of viral capsid symmetry?
Helical (filamentous), icosahedral (spherical), and complex.
What is the function of viral spike proteins?
Help viruses attach to host cells.
What are the types of viral genomes?
Either DNA or RNA, single or double-stranded, linear or circular.
What methods are used to detect viruses?
Traditional: viral cultures, immunoassays. Modern: PCR, sequencing, electron microscopy.
What is a plaque assay?
A method to measure virus infectivity by counting plaques formed on a cell monolayer.
What did the Hershey-Chase experiment demonstrate?
That DNA, not protein, carries genetic information.
What are the phases of viral replication?
Attachment, entry, synthesis, assembly, release.
What is lysogeny?
Viral genome integrates into host DNA and replicates with it without causing immediate lysis.
What is the Baltimore classification?
System that classifies viruses based on their genome type and replication strategy.
What is a viroid?
Infectious RNA without a protein coat, mostly affecting plants.
What is a prion?
Infectious protein without nucleic acid, causes diseases like CJD and BSE.
How do RNA viruses replicate?
They use RNA-dependent RNA polymerase to replicate their genomes.
What immune defenses target viruses?
RNA interference, CRISPR, restriction-modification, antibodies, and interferons.
What makes a host cell ‘permissive’ to viral replication?
It supports the complete replication cycle of the virus.
What are examples of viral prevention and treatment methods?
Vaccines, pre-formed antibodies, interferons, antivirals.
