Quiz 6 Viruses Flashcards Preview

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Flashcards in Quiz 6 Viruses Deck (30):

What are the components of viruses?

Nucleic Acid Core (DNA or RNA), Capsid (protein coat), Envelops (some viruses have this lipid bilayer membrane), spikes and Viron is a complete virus particle.


What are the reproduction capabilities of a virus?

Viruses can replicate, or multiply only inside a living host cell, therefore they are obligate intracellular parasites.


What are naked viruses?

Viruses with a nucleocaspid and no envelope.


What are spikes?

Spikes are projections that extend from the viral envelope that aid in attachment to the host cell.


What are glycoproteins?

Surface projections that attach virions to specific receptor sites on susceptible host cell surfaces.


Envelops help the virus in____by the host's immune system.

evading detection


What determines the shape of viruses?

Capsomeres or envelope.


What are the 4 shapes of viruses?

Helical capsid (ribbion like protein spiral around the nucleic acid), Polyhedral capsid (many sided, most common is icosahedron), Bullet shaped and spherical.


How are viruses classified?

Viruses are classified by the type of host/host structures they infected.


What are the classification of viruses?

Bacteriophages, Plant viruses and Animal viruses (subgrouped by tissues they attack: Dermotrophic and Neurotrophic).


What are the biochemical and molecular classifications of viruses?

Type and structure of their nucleic acids, method of replication, host range, and other physical and chemical characteristics.


What are the nucleic acid classification of viruses?

DNA or RNA, RNA+DNA viruses can be ss/ds, RNA viruses either carry enzymes or have genes for those enzymes in order to copy RNA genomes after infecting a host cell.


What is the replication process of + ssRNA?

Many have +sense RNA act likes mRNA translates directly by host's ribosomes during infection.


What is the replication process of -ssRNA?

The RNA acts as a template during transcription to make a complementary + sense mRNA. Must carry a RNA polymerase.



small, naked, polyhedral and + sense RNA viruses.
Ex. enterovirus, hepatovirus, and rhinovirus.



- sense RNA virus, medium sized, enveloped viruses. Helical and bullet shaped.


Viral Replication Process

Absorption (attachment), Penetration (entry), Synthesis (new nucleic acids, caspid proteins), Maturation (assembly of new synthesized viral stuff), and Release.


Unlike bacteriophage, animal viruses do not have a mechanism for...

injecting their nucleic acid into host cells.


How do most naked viruses enter the cell?

By endocytosis which is when virions are captured by pit-like regions on cell surfaces.


When does uncoating occur?

After animal viruses enters host cell's cytoplasm and separates genome from protein coat.


What are the 2 discoveries of culturing animal viruses?

Discovery and use of antibiotics to prevent bacterial contamination.
Discovery of proteolytic enzymes can free animal cells from surrounding tissues w/o injuring freed cells.


Types of cell cultures.

Primary (directly from animal), Diploid fibroblast strains (most widely used and support growth of a wide range of viruses), Continuous cell lines (cells that reproduce for generations HeLa)


What is the Cytopathic Effect (CPE)

1.Visible effect viruses have on cells.
2. Cells have common effects are cell shape, and detachment. 3.Distinctive, used as an ID of the infecting virus. 4.Syncytia: giant multinucleate cells caused by fusion.


What is teratogen?

Induction of effects during embryonic development.


What are the 3 human viruses accounting for a large number of teratogenic effemegalcts are:

1. Cytomegalomvirus
2. Herpes simplex virus I & II


What are the 3 viruslike agents?

Satellites, Virioids, and Prions.


What are satellites?

Small single-stranded RNA molecules that lack genes for replication. In the presence of a helper virus they can replicate.


What the 2 types of satellites?

Satellite: associated w/ plants.
Nucleic acids.


The discovery of viriods.

By T.O. Diener when studying potato tuber spindle disease. So he proposed an infectious RNA particle smaller than a virus.


What are the 6 differences of viroids to viruses?

1. Single circular RNA molecule of low MW.
2.Exist in cells (nucleoli as particles of RNA w/o capsids/envelopes.
3. Don't need helper virus
4. Viroid RNA does not make proteins.
5. Viroid RNA is always copied in host cell nucleus.
6. Not apparent w/o ID.