Читать книгу Principles of Virology - Jane Flint, S. Jane Flint - Страница 58

1 What is the definition of a virus?

2 Which is a key property first discovered about viruses that distinguished them from other microorganisms?They were too large to pass through a 0.2-micron filterThey could reproduce only in brothThey made tobacco plants sickThey were small enough to pass through a 0.2-micron filterNone of the above

3 All of us carry many different viruses throughout our daily lives. Why don’t they make us sick?

4 Why do we care that viruses comprise the most biodiversity on the planet?

5 The first viruses were discovered near the end of the 1800s. How was this done?By transmitting a disease to tobacco plants using a cell-free filtrate of diseased leavesPasteur showed that viruses could reproduce in a sterile mediumLeeuwenhoek saw viruses in his microscopeRobert Koch showed that viruses grown in broth could cause diseaseAll of the above

6 Why were the bacteriophage systems so useful for elucidating principles of viral reproduction? What important features of virus-host interactions were discovered from these studies?

7 How are viruses classified?

8 How does the discovery of new viruses today differ from 100 years ago?

9 Which host cell function is essential for the reproduction of all viruses?

10 What is the basis of the Baltimore classification system? How many genome types are sufficient to describe all viral families in this system?