Viral Structure and Classification
Name a difference between enveloped and non-envelopd viruses
Presence of lipid bilayer envelope, enveloped viruses are less environmentally stable, enveloped viruses must be released from the host cell via budding
This is the part of the cell where most DNA viruses replicate.
The nucleus
This is an example of antigenic drift of the influenza virus
Small graduate mutations (point mutations) that change viral proteins (seasonal flu variants)
Rhinovirus, the cause of the common cold, would be an example of a(n) ________ infection.
acute
This is the virus that infects humans that we have succeeded in completely eradicating.
Small pox (Vaccinia virus)
Name one virus in the Baltimore Group IV
Poliovirus, Flavivirus, Coronavirus
This is the enzyme retroviruses require to make DNA from RNA
Reverse transcriptase
This is an example of antigenic shift of the influenza virus.
Abrupt genetic change due to reassortment or recombination, creating new viral subtypes (example - those that can cause pandemics)
Define viral latency. Give an example
When a virus infects a cell and integrates its genome with the host cell with no active viral replication. Example - Herpes
Abreva is an antiviral that prevents _________ from ________.
Herpes, attaching and entering host cell
This structural protein mediates entry of influenza into host cells
Hemagglutinin (HA - H of the H_N_)
(-) sense RNA viruses need to do this before they can begin replicating inside the host cell.
Convert (-) sense RNA to (+) sense RNA
A virus that contains a proofreading enzyme for genome replication will mutate ________ frequently than a virus that does not.
less
HIV will establish a _________ infection.
latent (if treated successfully)
HIV is usually treated through a combination of antiviral drugs. One of those drugs will almost assuredly inhibit ______________.
reverse transcription
This structural feature allows bacteriophage to bind to their host cell
Tail fibers
Temperate phage are capable of both the ______ cycle and the ________ cycle.
lytic, lysogenic
This is the tradeoff hypothesis in viral evolution
Viruses must balance virulence with transmissibility. Extremely deadly viruses may limit their own spread if host dies too quickly.
It is easier for the immune system to recognize and respond to _______ infections over _______ infections.
acute, latent or chronic
Tamiflu, Relenza, and Xofluza are used to treat influenza infections. These drugs work by inhibiting ________ or __________.
Tamiflu/Relenza - Viral exit (neuraminidase inhibitors)
Xofluza - Viral genome replication (synthesis stage)
These Baltimore virus classification groups contain ssRNA.
The cholera toxin that is responsible for the pathogenesis of the V. cholerae bacteria is produced because of a __________ presence in the V. cholerae genome.
prophage
RNA viruses mutate more frequently than DNA viruses. Retroviruses mutate most frequently of all.
Explain a mechanism by which viruses can induce malignant transformation of their host cells.
Express oncogenes, activate host proto-oncogenes, suppress host tumor suppressor proteins
Sovaldi is an antiviral drug for Hepatitis C that works by inhibiting the RNA-dependent RNA polymerase. This will affect the ________ stage of viral replication.
Synthesis (prevents genome replication and protein synthesis through translation)