Viro6

Question 1

counts the number of viruses in a specific volume to determine the virus concentration

Answer 1

Virus quantification

Question 2

the number of infectious units per ml of the sample

Answer 2

titer

Question 3

The Virus Titer is_____

Answer 3

lowest concentration of virus that still infects cells

Question 4

There are basically two types of viral quantification tests—

Answer 4

Biological

Physical

Question 5

This viral quantification tests depend on a virus particle initiating a successful replication cycle

Answer 5

Biological

Question 6

2 examples of biological quantification tests are:

Answer 6

Plaque assays
Pock assays

Question 7

These viral quantification tests do not depend on any biological activity of the virus particle

Answer 7

Physical

Question 8

Viral Quantification Tests

Answer 8

Question 9

The most direct method to determine the concentration of virus particles in a sample

Answer 9

Direct Particle Counts by Transmission Electron Microscopy (TEM)

Question 10

Using this technology, each sample is stained with two different fluorescent dyes, one specific for nucleic acid, and the other specific for protein, and analyzed as they flow through a laser beam

Answer 10

Virus Counter 2100

An example of direct counting of viral particles in solution

Question 11

This test is called a

Answer 11

Hemagglutination assay

Question 12

What is the most likely titer for this assay?

Answer 12

16 hemagglutination units per vial

Question 13

In this assay, purified viral antigens (standards) and viral particles through agarose gel seeded with polyclonal antisera against a viral antigen

Answer 13

Single Radial Immunodiffusion (SRID)

Question 14

A circular zone of necrotic cells surrounded by viable cells in a monolayer.

Answer 14

Plaque

Question 15

The number of virus particles capable of forming plaques per unit volume is given in units of___________

Answer 15

Plaque-forming Units/ml (PFU)

Question 16

Assuming this is the last plate which showed activity, quantify the clearly visible field in this assay for which 0.2 ml media was used. The dilution is 10^-4

Answer 16

28 PFU

Titer = (2.8 * 10⁵ PFU) / (0.2ml)

Titer = 1.4 * 10⁶ PFU/ml

Question 17

A necrotic area on chorioallantoic membrane [CAM] of embryonated egg is called a ______

Answer 17

Pock

Question 18

In a Transformation Assay, ______________

Answer 18

Transformed cells lose contact in-hibition and become heaped upon one another

Question 19

The assay which quantifies oncogenic viruses transforming cells in culture uses what units of measurement?

Answer 19

Focus-forming units/ml

Question 20

Virus dilution that affects 50% of the test subjects uses what kind of assay?

Answer 20

Quantal Assays

Question 21

The tissue culture infectious dose which will infect 50% of the cell monolayers challenged with the defined inoculum is called what?

Answer 21

TCID₅₀

Question 22

The average number of virus particles infecting each cell is called the ______

Answer 22

Multiplicity of infection (moi)

Question 23

The formula for the Reed and Muench Method for determining TCID₅₀ is___________

Answer 23

(% immediatly above 50% - 50) / ​(% immediatly above 50% - % immediatly below 50%)

Question 24

Calculate the TCID₅₀

in 0.1 ml

The calculation works, even though it’s not really for TCID₅₀

Answer 24

TCID₅₀= 10^8.6

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