Week 3 Reading Quiz: Class 4, 5, &6 Flashcards
Concentration of a virus in a sample
virus Titer
Measure of virus infectivity
PFU/mL
The linking of multiple red blood cells by virus particles resulting in a lattice basis of method to measure virus concentration
Hemagglutination
The number of infectious virus particles added per cell
Multiplicity of Infection
To calculate the titer of a virus in plaque-forming units (PFU) per milliter, (___) serial dilutions of a virus stock are prepared, and (_____) aliquots are inoculated onto susceptible cell monolayer
10-fold ; .1 ml
To minimize error in the virus titer, only plaques containing between () and () plaques are counted. (Fill-in-the-blank)
10; 100
What is the purpose of adding dye during a plaque assay?
a
To restrict viral diffusion.
b
To visualize dead cells for the purposes of counting individual plaques.
c
Used as a growth medium.
d
To visualize living cells for the purposes of counting individual plaques.
e
To enhance contrast between plaque and living cells
e
To enhance contrast between plaque and living cells
The distribution of virus particles per cell is best described by :
Poisson Distribution
In the multiplicity of infection (MOI) equation: P(k) = e(-m)m(^k)/k!, what does P(k) stand for?
a
fraction of cells infected by k virus particles
b
multiplicity of infection
c
fraction of virus particles inoculated onto k susceptible cells.
d
fraction of cells multiplied by # virus particles
Fraction of cells infected by k virus particles
What is the starting material that is used in a COVID-19 RT-PCR test?
a
DNA
b
RNA
c
Protein
d
Lipids
e
None of these answers
b. RNA
What region of the SARS-CoV-2 genome is typically identified in a patient sample?
a S gene (Spike glycoprotein)
b N gene (Nucleocapsid)
c
E gene
d
M gene
e
None of these answers
N gene (Nucleocapsid)
Please sort the following steps of polymerase chain reaction (PCR) in the correct order:
- Denaturation
- Annealing
- Extension
What is the 1st type of antibody that is detected in your blood after exposure to a virus and that is also measured in a COVID antibody test?
lgM
Which antibody circulates throughout your blood months to years after exposure/infection with a virus and that is also measured in a COVID antibody test?
lgG
What is the purpose of the gold nanoparticles in the COVID antibody test?
Used as visual indicators because of the nanoparticles interaction with light
All of the following have been used to name vial isolates EXCEPT:
a
Specific type of disease they cause
b
Where they were first isolated
c
Body sites they affected
d
Geographic locations
e
Scientists who discovered them
f
All of these answers are TRUE
f. All of these answers are true
All of the following are gene products encoded by viral genomes EXCEPT:
a
Replication
b
Complete protein synthesis/translation machinery
c
Assembly/packaging
d
Transmission/spread
e
Disrupt host defenses
f
All of these answers are TRUE
b. Complete protein synthesis/translation machinery
Viral genomes can be:
a
DNA or RNA
b
double stranded
c
single stranded : (+) strand, (-) strand , ambisense strand
d
linear
e
circular
f
segmented
g
gapped
h
All of the above
h. All of the above
Two universal functions of viral genomes are to:
a
kill the host cell ; evolve
b
produce mRNAs to be read by viral ribosomes ; serve as templates for synthesis of progeny genomes
c
produce mRNAs to be read by host ribosomes ; serve as templates for synthesis of progeny genomes
d
encode nucleic acid polymerase ; serve as templates for synthesis of progeny genomes
e
produce mRNAs to be read by host ribosomes ; evolve
c.
produce mRNAs to be read by host ribosomes ; serve as templates for synthesis of progeny genomes
mRNA/RNA that can be directly translated into protein is known as the ____strand, whereas the complement that cannot be translated is known as the ___.
plus, minus
DNA genomes are depicted as different shades of
_____
, whereas RNA genomes are shown as different shades of _____.
blue; green
Short single-stranded pieces of DNA that recognize unique regions of the viral genome and that bracket the target region of the N gene.
Primers
Enzyme that converts a single-stranded DNA copy of the viral RNA (also known as complementary DNA or cDNA).
Reverse transcriptase (RT)
Enzyme that extends second DNA strand to produce double-stranded DNA.
Taq DNA polymerase
Piece of equipment used to amplify segments of DNA via the polymerase chain reaction (PCR)
Thermal cycler
Polymerase extends/synthesizes new DNA strand
Extension
Primers bind to their target sequences
Annealing
DNA separates into single strands
Denaturation
