Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
50 Cards in this Set
- Front
- Back
|
what are the 8 steps in the virus life cycle?
|
attachment, penetration/entry, uncoating, transcription, translation, replication, assembly and exit/release
|
|
|
viral receptors will bind _____ cell associated proteins/receptors or carbohydrates.
|
specific
|
|
|
T/F
all cells in the body express the same proteins on their surface |
FALSE:
liver cells express liver specific receptors, neurons have neuron specific receptors, etc |
|
|
T/F
If i took the same protein from a monkey and a pig, they might have a slightly different amino acid sequence. |
FALSE
SIGNIFICANTLY different |
|
|
what is the host range?
|
specific species within which the virus can cause disease
|
|
|
individual viruses may demonstrate a ______ species-specific, host range for replication.
|
narrow
|
|
|
what two things can determine the host range?
|
the ability of the virus to attach and the ability of viral proteins to interact with any required intracellular proteins
|
|
|
as a group, viruses have a very ______ host range.
|
broad
|
|
|
how many viral proteins are expressed by the adenovirus? what do these viral proteins do?
|
two; bind to and induce dimer formation between cellular transcription factors to promote viral gene transcription
|
|
|
what does Echovirus 3 use for attachment?
|
CD55
|
|
|
what is the strandedness of the echovirus 3? is it enveloped and naked?
|
+ssRNA, naked
|
|
|
How is CD55 expressed?
|
in any cell or tissue that comes into contact with serum complement proteins
|
|
|
what is needed for the rabies virus to attach? where can this be found?
|
nicotinic acetocholine receptor; in neurons throughout the body, adipocytes, immune cells, endothelial cells and epithelial cells lining the intestines and lungs
|
|
|
what are the three mechanisms of membrane transport (into the cell)?
|
diffusion, active transport and endocytosis
|
|
|
how do viral proteins play an integral part in direct fusion?
|
the fusion involves contacts between viral receptors and cell surface receptors and then the viral proteins change the conformation to force the two membranes into contact and fusion.
|
|
|
how do bacteriophages deposit their genome into the cytosol?
|
by piercing cell membranes and depositing it
|
|
|
what triggers the lysis of the endosome?
|
pH change as the endosome prepares to fuse with the lysosome
|
|
|
what is uncoating?
|
the process of releasing the viral genome from virion components to make the genome accessible for replication or translation.
|
|
|
what is polymerase?
|
an enzyme that synthesizes a nucleic acid strand using another as a template
|
|
|
T/F
RNA polymerase I, II and III are all DNA dependent RNA polymerases. |
TRUE
|
|
|
what cellular aspect is RNA polymerase I responsible for?
|
Pre-rRNA
|
|
|
what cellular aspect is RNA polymerase II responsible for?
|
Pre-mRNA, snRNAs
|
|
|
what viral aspect is RNA polymerase I responsible for?
|
pre-mRNA, mRNA
|
|
|
what cellular aspect is RNA polymerase III responsible for?
|
Pre-tRNAs, 5S rRNA, U6 snRNA
|
|
|
what viral aspect is RNA polymerase I responsible for?
|
Ad2 VA-RNA, EBV EBER RNAs
|
|
|
which RNA polymerase synthesized the most cellular mRNA?
|
polymerase II
|
|
|
If i wanted to synthesize mRNA for translation of viral proteins, what would I need?
|
RNA-dependent RNA polymerase
|
|
|
what is required for replication or synthesis of new genomes in viruses?
|
RNA-dependent RNA polymerase
|
|
|
what is the sequence for translation of a (+)ssRNA?
|
(+) ssRNA --> translation via RNA polymerase -> (-) ssRNA ---> several (+) ssRNA---> 1 is tranlated into viral proteins and the others are packaged into new virions
|
|
|
what is the sequence for translation of a (-) ssRNA?
|
(-)ssRNA ---> RNA polymerase in virion --> several (+) ssRNA ---> translation into viral proteins via a new RNA polymera into many (-) ssRNA which is then packaged into new virions
|
|
|
T/F
synthesis of mRNAs always follows the same rules and mechanisms as cellular mRNA synthesis. |
false....
never pick a question that says always... usually it follows the same rules |
|
|
of RNA viruses, which genes have introns and/or alternate splicing?
|
only retrovirus genes
|
|
|
T/F
all viruses use cellular ribosomes for protein translation, including the cellular translation initiation machinery. |
true...
... tricky |
|
|
most DNA viruses use the _____ as the site of replication and transcription. except?
|
nucleus; pox viruses
|
|
|
most RNA viruses use the _______ as the site of replication and transcription. except?
|
orthomyxoviruses and retroviruses
|
|
|
most anti-viral therapy against DNA viruses, targets what?
|
DNA polymerase
|
|
|
pick the three viruses that have cellular DNA polymerase:
Parvovirus, papovavirus, adenovirus, herpesvirus (1, latent, productive), and poxvirus ? |
parvovirus (AAV2), Papovavirus (SV40), and Herpes virus (EBV latent)
|
|
|
define reassortment.
|
exchange of entire nucleic acid molecules
|
|
|
define mutation.
|
heritable changes in the nucleotide sequence of a segment of DNA or RNA
|
|
|
T/F
viral polymerases are as accurate as cellular polymerases. |
false
Viral polymerases are not as accurate as cellular polymerases |
|
|
Viral polymerases (in comparison to cellular polymerases) have _____ proofreading ability? what does this ability cause?
|
poorer; they accumulate mutations more rapidly and evolve into new strains and serotypes that can evade the immune system
|
|
|
what are prime candidates for antiviral therapy? why?
|
nucleoside analogs; because there are many chemical modifications that can be made to the basic structure
|
|
|
what inhibits 3 steps in HEP B life cycle?
|
entecavir
|
|
|
what are three targets of antiviral drugs?
|
viral uncoating, nucleic acid syntehsis and assembly and release of viral particles
|
|
|
which targets of antiviral drugs is effective against HIV?
|
assembly and release of viral particle and nucleic acid synthesis
|
|
|
Template switching can be found in which virus, RNA, DNA or both?
|
RNA
|
|
|
Homologous recombination can be found in which virus, RNA, DNA or both?
|
both
|
|
|
T/F
virions can be packaged with a segmented genome with 2 different strains of a virus. |
True: reassortment
|
|
|
How do naked viruses exit?
|
lysis
|
|
|
how do the enveloped viruses exit?
|
budding
|
