Measuring Virus Particles Techniques

Vincent Rock introduces 'Virus Watch', focusing on virus measurement techniques. He explains methods like electron microscopy, PCR, and immunological assays, highlighting their limitations in determining infectious virus counts. The plaque assay is detailed as a preferred method for measuring infectious viruses, with a step-by-step guide on its procedure. The video concludes with the significance of plaque assays and contact information for further inquiries.

Which technique is described as time-consuming and expensive for measuring virus particles?

• Plaque assay

• Immunological assays

• Electron microscopy

• PCR

What is the main limitation of using PCR to measure viruses?

• It is too expensive

• It requires a lot of samples

• It does not measure infectious viruses

• It is too slow

In a plaque assay, what substance is used to restrict virus spread to neighboring cells?

• Cellulose

• Starch

• Gelatin

• Agar

What is the purpose of using a semi-solid medium in a plaque assay?

• To enhance virus replication

• To restrict virus spread to neighboring cells

• To change the color of the medium

• To make the medium more nutritious

What temperature is used to adsorb the virus to the cells in a plaque assay?

• 45 degrees Celsius

• 50 degrees Celsius

• 37 degrees Celsius

• 25 degrees Celsius

What is the role of trichloroacetic acid in the plaque assay process?

• To fix the cells to the plastic

• To stain the cells

• To neutralize the virus

• To dissolve the agar

How is the virus titer expressed in a plaque assay?

• In terms of viral genomes per ml

• In terms of viral load per ml

• In terms of plaque forming units per ml

• In terms of cell count per ml

Why do some virologists prefer PCR over plaque assays?

• PCR is faster and less labor-intensive

• PCR measures both infectious and non-infectious viruses

• PCR is more accurate

• PCR is cheaper

What is the main advantage of a plaque assay over PCR?

• It is less expensive

• It measures the number of infectious viruses

• It requires less equipment

• It is faster

What does the 'wall of polio' refer to in the context of the video?

• A display of virus images

• A wall of laboratory equipment

• A stack of plates used for plaque assays

• A collection of virus samples