Exam 19: Viruses

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur?

Use the following information to answer the following questions. In 1971, David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA. The table below shows the results of testing five viruses for nuclease specificity, the ability of the virus to act as an mRNA, and presence (+) or absence (-) of its own viral polymerase. Virus Nuclease Sensitivity Genome as mRNA Polymerase A Dnase - + Rnase + - Dnase - + Rnase - + Rnase + - -Based on the above table, which virus meets the requirements for a bacteriophage?

Which of the following is characteristic of the lytic cycle?

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

Which of the following is the best predictor of how much damage a virus causes?

If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities?

Which treatment could definitively determine whether or not the component is a viroid?

What is the name given to viruses that are single-stranded RNA that acts as a template for DNA synthesis?

Most molecular biologists think that viruses originated from fragments of cellular nucleic acid. Which of the following observations supports this theory?

Most human-infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis?

The difference between vertical and horizontal transmission of plant viruses is that

Use the following information to answer the following questions. In 1971, David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA. The table below shows the results of testing five viruses for nuclease specificity, the ability of the virus to act as an mRNA, and presence (+) or absence (-) of its own viral polymerase. Virus Nuclease Sensitivity Genome as mRNA Polymerase A Dnase - + Rnase + - Dnase - + Rnase - + Rnase + - -Based on the above table, which virus meets the Baltimore requirements for a retrovirus?

What are prions?

Use the following information to answer the following questions. In 1971, David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA. The table below shows the results of testing five viruses for nuclease specificity, the ability of the virus to act as an mRNA, and presence (+) or absence (-) of its own viral polymerase. Virus Nuclease Sensitivity Genome as mRNA Polymerase A Dnase - + Rnase + - Dnase - + Rnase - + Rnase + - -Given Baltimore's scheme, a positive sense single-stranded RNA virus such as the polio virus would be most closely related to which of the following?

Emerging viruses arise by

Which of the following describes plant virus infections?

What characteristics of electron microscopes make them most useful for studying viruses?

Why do RNA viruses appear to have higher rates of mutation?