Question

Plaque assays are often used to estimate the number of virions in a sample of a particular volume (the titer). The count is given as plaque-forming units. Which of the following is NOT generally a concern that must be considered in evaluating the results of plaque assays?
a.The plaques must be at a density that can be counted on the plate; high and low densities may result in inaccurate counts.
b.The plaques must be clearly visible in order to be counted accurately; this technique cannot be used with viruses that do not cause clear cellular damage.
c.The largest problem is that single viruses may create multiple plaques, resulting in overestimates of the number of viruses present.
d.The largest problem is that the count may underestimate the total number of viral particles, as not all virions may be able to cause infection.

Answer 1

Answer:

c) The largest problem is that single viruses may create multiple plaques, resulting in overestimates of the number of viruses present.

Explanation:

• Plaque-based assays are the accepted method used for finding virus concentration in terms of infectious dose.
• Viral plaque assays determine the number of plaque forming units (pfu) in a virus sample, which is one measure of virus quantity.