Exam 14: Viruses

When comparing different viral species, some genes can be clearly identified as being related due to their sequence similarity, which indicates a common lineage between two species. However, in some instances other genes can also be found that are completely unrelated and thus contradict evidence of shared ancestry. Such observations could be explained by

A previously unknown virus is discovered in an isolated population of mammals. Several mammals are found to be infected with the virus but display few symptoms. Based on this observation, the mammal population is likely to have been exposed to this virus

Which of the following statements about viruses is INCORRECT?

An unknown virus is being studied in a molecular biology lab. A scientist deduces that in order for this virus to replicate after infecting a suitable host cell, it must use a replicase complex that includes both viral and host proteins. Based on this, the scientist is able to determine that this virus must have a genome comprised of

Under what specific conditions is a satellite virus able to replicate?

Which of the following is an example of a retrovirus?

A retrovirus has a ssRNA genome. When it enters a host its genome is transcribed and incorporated into the host genome. As such, its replication strategy from infection through to the creation of new viral particles must be

You are working in a molecular virology laboratory, studying a diseased tropical plant. You identify a circular ssRNA genome that is 350 nucleotides in length. No other viruses are infecting the plant. Which of the following statements in relation to these observations is CORRECT?

Which of the following does NOT occur when a virion infects a suitable host?

What is the correct definition of a viral genome?

Molecular biological techniques have developed with the study of viruses. One such technique used to help confirm the existence of viruses was

You have extracted total protein from a mutant virus that lacks any a specific enzyme activity, and discover that the extract contains several very large proteins. You compare this to a similar extract taken from a wild-type population of the same species and discover there are no very large proteins, but you do observe additional smaller peptides. How can you explain this result?

A seriously ill child has presented to Emergency at a hospital. He is showing symptoms of cerebral dysfunction, anxiety, confusion and agitation. The only clue as to the origins of the illness is that the child has been recently handling fruit bats. The first doctor to examine the child suspects the bat was a host for a viral infection, while the second suspects the child has been bitten by mites from the bats. Which doctor's treatment should be given priority based on the information provided?

Which of the following can be used as an effective vaccine against viral disease?

A proteinaceous infectious particle is also known as a

In the biochemical life cycle of a virus, which phase follows immediately after the transmission phase?

A human population is struck down by a viral epidemic resulting in a high percentage of mortality. Virologist one argues that this is most likely due to the virus having mutated, while virologist two contends that the virus has switched hosts. Which virologist is most likely to be correct and why?

Why has the study of viruses been integral to the development of molecular biology?

Why are many retroviruses also associated with an increased risk of cancer?

Which of the following is least likely to be a shared feature of a viral genus or group?