Week 3 Reading Quiz: Class 4, 5, &6

Question 1

Concentration of a virus in a sample

Answer 1

virus Titer

Question 2

Measure of virus infectivity

Answer 2

PFU/mL

Question 3

The linking of multiple red blood cells by virus particles resulting in a lattice basis of method to measure virus concentration

Answer 3

Hemagglutination

Question 4

The number of infectious virus particles added per cell

Answer 4

Multiplicity of Infection

Question 5

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

Answer 5

10-fold ; .1 ml

Question 6

To minimize error in the virus titer, only plaques containing between () and () plaques are counted. (Fill-in-the-blank)

Answer 6

10; 100

Question 7

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

Answer 7

e

To enhance contrast between plaque and living cells

Question 8

The distribution of virus particles per cell is best described by :

Answer 8

Poisson Distribution

Question 9

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

Answer 9

Fraction of cells infected by k virus particles

Question 10

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

Answer 10

b. RNA

Question 11

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

Answer 11

N gene (Nucleocapsid)

Question 12

Please sort the following steps of polymerase chain reaction (PCR) in the correct order:

Answer 12

1. Denaturation
2. Annealing
3. Extension

Question 13

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?

Answer 13

lgM

Question 14

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?

Answer 14

lgG

Question 15

What is the purpose of the gold nanoparticles in the COVID antibody test?

Answer 15

Used as visual indicators because of the nanoparticles interaction with light

Question 16

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

Answer 16

f. All of these answers are true

Question 17

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

Answer 17

b. Complete protein synthesis/translation machinery

Question 18

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

Answer 18

h. All of the above

Question 19

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

Answer 19

c.

produce mRNAs to be read by host ribosomes ; serve as templates for synthesis of progeny genomes

Question 20

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 ___.

Answer 20

plus, minus

Question 21

DNA genomes are depicted as different shades of
_____
, whereas RNA genomes are shown as different shades of _____.

Answer 21

blue; green

Question 22

Short single-stranded pieces of DNA that recognize unique regions of the viral genome and that bracket the target region of the N gene.

Answer 22

Primers

Question 23

Enzyme that converts a single-stranded DNA copy of the viral RNA (also known as complementary DNA or cDNA).

Answer 23

Reverse transcriptase (RT)

Question 24

Enzyme that extends second DNA strand to produce double-stranded DNA.

Answer 24

Taq DNA polymerase

Question 25

Piece of equipment used to amplify segments of DNA via the polymerase chain reaction (PCR)

Answer 25

Thermal cycler

Question 26

Polymerase extends/synthesizes new DNA strand

Answer 26

Extension

Question 27

Primers bind to their target sequences

Answer 27

Annealing

Question 28

DNA separates into single strands

Answer 28

Denaturation