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60 Cards in this Set
- Front
- Back
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Tell about viruses
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non-living particles/acellular, has a genome & a capsid, either RNA or DNA except Cytomegalovirus, obligate intracellular parasite (need of host), are haploid except retroviruses which are diploid
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What doesn’t contain a virus?
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ADP/ATP, AA, Sugars, ribosomes
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T or F : viruses are not protected from much of the immune response
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F
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If u want to see a virus, count how many and observe the shape, which microscope do u use?
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Electron microscope
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What disease does the smallest virus cause?
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Yellow Fever w size of 22 nm
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T or F: the smallest bacteria is similar in size to the largest virus
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T
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T or F: DNA gives orders to RNA which makes proteins
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T
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How do viruses reproduce?
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Via an Assembly process of new viral particles
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T or F: the capsid is derived from the host cell
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F
The envelope is |
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T or F
the genome is not surrounded by the capsid |
F
is always surrounded by the capsid |
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T or F
capsid is made up of proteins subunit called capsomers |
T
many capsomers form the capsid |
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What r the 2 medically important virus nucleocapsid structure?
Are they assymetrical? |
Helical & icosahedral
No they are symmetrical |
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What are complex viruses?
Give Ex. |
Ans: Those whose capsid is made out of a double protein layer
Ex: poxviruses & retrovirus |
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T or F
the envelope is derived from the host cell |
T
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T or F
Most enveloped viruses can survive the harsh GI tract environment |
F
they cannot |
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T or F: most of the animal viruses are enveloped
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T 13/20
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Complete :
… is easily disrupted by acid, detergents, drying, organic solvents. Therefore … Must remain wet & r transmitted in fluids/secretions such as blood, tissue, respiratory/vaginal |
Enveloped virus
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What protects the virus core or the genome?
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Capsid and envelope
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What r the functions of envelope (or capsid, when there is no env.)?
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Host cell recognition & binding to host cell upon infection
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What r Naked viruses?
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The ones w/o an envelope
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What r capsid + genome?
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Nucleocapsid
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What r the parts of a virus?
What r the subparts of these parts? |
Parts: Covering and Viral core
Subparts: a) capsid & envelope(not all) b)DNA/RNA & viral enz. (not all) |
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What r the type of mutant virus? Define each.
Where do they happen? |
They happen in the covering.
Type, m virus but responding differently to antibody detection (serotypes), outermost structure changes= diff symptoms Strain, m virus but located in Diff geographical areas & patients Variant: phenotype diff from wild-type |
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T or F: Only DNA virus has segmented genome
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F
only RNA |
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What is an isolate?
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Name given prior to genomic analysis, no info about the virus is recorded
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Where do Spontaneous mutations happen?
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in the viral genome
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T or F : viral DNA pol r more prone in error than viral RNA pol
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F
it ‘s the inverse because Viral RNA pol has no proofreading capabilities |
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What is the terrible & unique feature of a retroviruse?
What is it called? |
They contain r RNA virus w a dependent DNA pol (they replicate ultra fast)
it’s called Reverse Ttranscriptase |
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What r the type of mutation that happen in the viral genome?
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Spontaneous mutation
& gene rearrangement (by reassortment/ recombination) |
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Diff between Reassortment
& Recombination |
Recombination: exchange between 2 distinct genome, also called Strand Switching
ReaSSortment: exchange between 2 segmented genome, Strain of Influenza virus A, need to be vaccinated Q Y/O |
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Why is the genetic diversity relevant to human disease?
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Its explains
Drug resistance (ineffective) New host Recognition Escaping antibody recognition (phenotype) |
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How long is usually a viral cycle?
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From 8 (polioviruses) to 36 (herpes viruses) hrs
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What r the steps in viral propagation?
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Adsorption, attachment (tropism=affinity), Penetration, uncoating, Synthesis, Assembly & Release from host cell
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T or F
Naked virus enters entirely the host cell |
F
the envelope does because it’s from the host cell membrane |
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What are spikes, where r they found?
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Ligand for interaction w the host cell receptor, found in enveloped virus
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T or F : Spikes r only found in enveloped virus
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T
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The genome enters the host cell, unique to Naked virus:
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Direct Penetration
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The genome + the capsid enters the host cell, unique to Enveloped virus
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Fusion
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What is Endocytosis?
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Internalization of Clathrin/caveolin coated pits @ cell membrane
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T or F
Synthesis of mRNA from a DNA viral genome can be direct (ds DNA) or through a dsDNA intermediate (+ssDNA) |
T
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T or F:
Synthesis of mRNA from an RNA viral genome can be direct or through a dsDNA intermediate, or in the case of +RNA viruses, the genome itself is used as the mRNA |
T
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Where does RNA genome replicate? What about DNA genome?
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RNA: in cytoplasm, DNA: in nucleus except Pox Viruses (in cytoplasm)
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What r the 3 mechanisms for release of the virions from the host?
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Budding (become enveloped by this process), Cell lysis (viral load caused by naked virions), Exocytosis
Diff between Budding & Exocytosis: the latter do not acquire a portion of the host membrane |
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What is Cytopathic effect?
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Virus-induced damage within host cell, change in shape, size & presence of inclusions bodies
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What r the type of cytopathic effect?
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Inclusions bodies, Syncytium formation (giant multi-nucleated cell by enveloped vir.), Stopping cellular processes, membrane permeability (ions influx), lysis (fluid influx), apoptosis
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What r the non-cytopathic effect?
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Altered shape, detachment from substrate and transformation from cellular/viral oncogenes
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Which process doesn’t elicit an inflammatory response?
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Apotosis
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Complete: … gives the virus easy access to food and it also avoids immune system detection
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Syncytium formation
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What r the colorimetric assay? R they specific and sensitive?
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ELISA and Western Blot, yes
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Which uses light?
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Immunofluorescence assays
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T or F:
Direct/Sandwich assays detect viral antigen and indirect detect anti-viral antibodies |
T
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Which technique is describe below: small amount of DNA is needed, infectious agent is not needed, after growth of DNA infectious agent can be identified
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PCR
Polymerase Chain Reaction |
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What genome is needed for RT-PCR?
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RNA, DNA can be made back and then, the virus will be identified
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Which technique is described below: A strand of the viral nucleic acid (mRNA) will be matched (hybridized) w a strand of complementary nucleic acid
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Nucleic acid hybridizations
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T or F
Spots called pocks seen in chicken embryo is a positive answer to viral attack |
T
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Which one are the best lab techniques for immediate treatment?
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ELISA & PCR
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Which type of genome has the shortest life cycle?
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+ss RNA
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T or F
Enveloped are easily deactivated |
T
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How does acyclovir work?
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The viral changes the monophosphate to a triphosphate, acyclovir comes in and take advantage of the triphosphate.
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What is the order, family, subfamily, genus and species names end in for virus?
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Virales, viridae, virinae, virus, virus
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