Study questions Topic 1 (Introduction to virology)

What is a virus?

  1.  What are the two facts that provide an underlying simplicity and order to viruses?
  2. A viral genome must make mRNA: TRUE OR FALSE? Does it ever encode the ability to decode that mRNA?
  3. What is a virus?
  4. Do all viruses make you sick?
  5. Why is studying viruses an exercise in cell biology?
  6. What does (+) and (‐) strand RNA mean? What is (+) and (­‐) strand DNA?
  7. What is the Baltimore system? What does it tell us?

Unconventional viruses or atypical viruses

  1. What is a viroid? How does it replicate? Does it encode proteins? How does it make plants sick? How do satellites differ from viroids?
  2. Name a satellite involved in human disease.   Why is HDV a hybrid between viroid and satellite? How do prions cause disease?
  3. What are the three different types of spongiform encephalopathies? Explain mad cow disease and why it scared people.
  4. Why can’t mouse pathogenic prions cause disease in hamsters? True or false: all known prions cause disease.


Think Questions

We just learned that most viruses are much smaller than bacteria.

  1. Compare the sizes of viruses and bacteria.
  2. Why are viruses able to be so much smaller than bacteria?

Short answer questions

  1. In general, what can you say about the size of most viruses in relation to bacteria?
  2. Small, circular, single-stranded molecules of infectious that cause a few plant diseases such as potato spindle-tuber disease, cucumber pale fruit, citrus exocortis disease, and cadang-cadang (coconuts) are called ____________
  3. Infectious proteins particles thought to be responsible for a group of transmissible and/or inherited neurodegenerative diseases including Creutzfeldt-Jakob disease, kuru, and Gerstmann-Straussler- syndrome in humans as well as scrapie in sheep and goats are called ______________
  4. Normal sterilization procedures may not necessarily prevent the transmission of prion diseases. Why might this be?