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Gram Stains
Anatomy, Shape, Arrangements

Worksheet – Ubiquity

Section 1

Indicate whether the following statements are True or False.

1. The only places in your body where microbes are found is where your tissues contact the environment.

2. Living microbes cannot be found in boiling hot springs or in frozen ice.

3. Most bacteria cannot be grown in a Petri dish.

4. Your colon and skin represent areas of your body that are commonly inhabited by bacteria.

5. Your blood and urine are commonly inhabited by bacteria.

6. The oldest bacterial spores brought back to life were 2500 years old.

7. The person most responsible for discovering the ubiquity of microbes was Alexander Fleming.

8. The acronym VBNC stands for “various bacteria, not coliforms”.

9. Finding bacteria on dust particles led to the development of pasteurization.

10. The theory of Spontaneous Generation is also called Abiogenesis.

11. Pasteur’s experiments found more bacterial contaminants in the air of cities than in the air on mountains.

12. The length of time a sterile container is opened to the air does not impact the chance of contamination.

13. Any count of microbes from an environmental sample probably undercounts due to VBNC organisms.

14. Water samples from a geyser and from ice would likely have the same airborne contaminants present.

15. Preventing contamination is the reason plates and tubes of media in the lab are kept closed.

16. Preventing contamination in the lab is the reason media and instruments are sterilized prior to use.

17. Autoclaving media is a non-lethal means for dissolving media to prepare it for use in the lab.

18. The term ubiquitous means “unique”, “special”, or “noteworthy”.

19. Canned foods are sterile because lack of oxygen prevents the growth of contaminating bacteria.

20. One way to demonstrate the ubiquity of bacteria would be to expose agar plates to water from a lake.

Section 2

Answer the following open-ended questions.

21. The amount of time an agar plate is exposed to air determines the amount of contamination it will detect, but contamination in water does not require keeping the plate open for a prolonged period – simply swabbing the surface is adequate. Why?

22. You place a sterile agar plate by a construction site in town and another at a ski lodge in the mountains, both opened to the air for 8 hours. What would be the expected results from this experiment?

23. You go to a rodeo and open two plates. Why would an agar plate left open for 1 hour be expected to have fewer contaminants appear after incubation than would an identical plate opened for 8 hours?