Bacteria and Virus Concept Questions

1. Why are bacteria classified in their own kingdom and not with plants, animals, protists, or fungi? (prokaryotic)

2. What features are shared by all prokaryotes? (no membrane bound nucleus)

3. What feature(s) might cause cyanobacteria to be classified as plants by some taxonomists? (chlorophyll/photosynthesis)

4. Describe three shapes that bacteria can have. (cocci, bacilli, spirilla)

5. Why is endospore formation important to bacteria? (survive long periods of harsh conditions)

6. Describe binary fission. (one cell elongates and splits into two)

7. What is conjugation in bacteria? Why is it important? (transfer of DNA from one cell to another. Increases diversity)

8. How is conjugation different from transformation? (conjugation - transfer of DNA; transformation - uptake of DNA from another cell or medium)

9. A protective slime coat around some species of bacterium known as a ____ makes them more capable of causing disease. (capsule)

10. Why are bacteria considered more primitive than protists? (no nucleus)

11. How do obligate aerobes differ from facultative aerobes? (obligate must have oxygen; facultative will use it if available)

12. _____ are organisms that die in the presence of oxygen. (obligate anaerobes)

13. Bacteria belong to a group of organisms known as prokaryotes. Discuss the differences between eukaryotes and prokaryotes in terms of cell wall, nuclear membrane, and chromosomes. (prokaryote cell wall of peptidoglycan, eukaryote of cellulose of chitin (where present); prokaryote no nuclear membrane; prokaryote usually one circular chromosome)

14. Why does dried or salted food resist spoiling by bacteria? (the salt removes most of the water)

15. Give specific examples showing the importance of microbial sterility in

a) your kitchen (prevent food borne bacterial illness)

b) a microbiology lab (prevent contamination)

16. Describe the results if all bacteria died. (no decomposition)

17. Why is there controversy as to whether a virus is living or non-living? (they show some but not all characteristics of living things)

18. Could you accept the hypothesis that viruses were the precursors to life on this planet? Explain. (No. Viruses require living cells to reproduce)

19. What are the main parts of a virus? (protein coat/shell/capsid and nucleic acid)

20. Suppose you were trying to develop a way to stop a virus from infecting a cell. How could this be done? (change the cell markers or change the protein shell of the virus)

21. Describe how viruses can be spread. (by droplets in the air, water, or body fluids)

22. The shape of a virus is determined by its _______. (capsid)

23. Do viruses and bacteria cause disease in the same way? Explain. (viruses kill cells, bacteria usually produce toxins or interfere with other cells)

24. Do you think viral infections are difficult to treat? Why or why not? (Yes. Virus is inside the host cells and difficult to kill without killing the host cell)

25. How is it that a virus is quite specific in the type of cell that it can infect? (capsid proteins recognize specific cell markers)

26. Explain how each of the following is effective in protecting food against microorganisms: salting, freezing, sterilization, boiling, antibiotics. (salting - removes water; freezing - stops growth microbes; sterilization - kills microbes; boiling - kills microbes; antibiotics - kills bacteria)