Question

1. Viral plaque assays are used for

A) Evaluation of the cancer-causing ability of a virus

B) The cultivation of viruses that cannot be grown any other way

C) Study of prions

D) Estimation of the number of infectious units present in a solution that contains viruses

2. Animal viruses can be assayed by

A) Observing viral plaques on a monolayer of animal cells

B) using the dilution streak plate method

C) Observing viral plaques on a lawn of bacterial cells

D) SPreading the virus on a culture plate seeded with E.coli

Answer 1

Question 1 answer- D) Estimation of the number of infectious units present in a solution that contains viruses.

Explanation- Viral plaque assays determine the number of plaque forming units (pfu) in a virus sample, which is one measure of virus quantity. This assay is based on a microbiological method conducted in petri dishes or multi-well plates.

Question 2 answer- A) Observing viral plaques on a monolayer of animal cells.

Explanation- Plaque assays enable the counting of local lesions produced by an animal virus in cell culture. The plaque assay consists of the inoculation of a statistically adequate yet easily countable number of infective virus particles onto an immobilized layer of host cells.

Bacterial cells can't be used for such assey.

Streak plate method is a technique used to isolate a pure strain from a single species of microorganism, often bacteria.