Exam 19: Viruses

Cells were infected with approximately 1,000 copies of either virus A or virus B at the 0 time point. At five-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per millilitre of culture was determined. -Using the data in the figure, how long does it take for virus A to go through one lytic cycle?

Which of the following statements best reflects what we know about how the flu virus moves between species?

A person is most likely to recover from a cold due to viral infection if the infected cells are able to perform which of the following processes?

Which of the following statements correctly describes vaccines and how they help prevent viral infection?

You isolate an infectious substance capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus or prion. You have four methods at your disposal to analyse the substance and determine the nature of the infectious agent. I. Treat the substance with enzymes that destroy all nucleic acids, and then determine whether the substance is still infectious. II. Filter the substance to remove all elements smaller than what can be easily seen under a light microscope. III. Culture the substance on nutritive medium, away from any plant cells. IV. Treat the sample with proteases that digest all proteins and then determine whether the substance is still infectious. - If you already know that the infectious agent was either a virus or a prion, which method(s) listed above would allow you to distinguish between these two possibilities?

- In the figure, when new viruses are being assembled at the point marked IV, what mediates the assembly?

A population of viruses with similar characteristics is called a ________.

Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell?

In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following regulation mechanisms would you expect of the genes of a bacteriophage?

Which of the following descriptions correctly identifies the main structural differences between viruses with envelopes and viruses without envelopes?

Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations?

Which of the following characteristics, structures, or processes is common to both bacteria and viruses?

RNA viruses require their own supply of certain enzymes because

The host range of a virus is determined by ________.