Thursday, October 20, 2011

Scribe Post for Thursday, October 20, 2011

Today in Class...
  • finished and went over UP. 33

  • finished bacteria notes

  • recorded data in both bacteria labs (UP. 19-25)

Today's Homework...

  • finish lab analysis (UP. 19-25)

  • read textbook Chapter 24 and finish note sheet

  • work on disease script---due on Halloween

  • work on spice lab (Up.39-42)

UP. 33 Antibiotics

III. Analysis

1. Which of the antibiotics would you use to prevent the growth of B. subtilis?


2. Which of the antibiotics would you use to prevent the growth of E.coli?


3. Are both organisms equally sensitive to each of the antibiotics used? Explain.

No because there are size differences in the zone of inhibitions.

4. Which of the two organisms is more sensitive to antibiotics in general?

B. subtilis.

5. If you wanted to inhibit both organisms with one antibiotic, which one would you use?


6. If E.coli is beneficial and B.subtilis is harmful and you were infected with both, which antibiotic would you choose?


7. In general, what can you conclude about bacteria and antibiotics from this experiment?

Antibiotics are specific at which bacteria they cure the best.

8. What feature does this experiment lack which it should have included?

A control group.

9. How would you correct this mistake?

Add a paper disk with no antibiotic in both petri dishes.

Important Information in the Notes

Power of Antibiotics

  • Zone of Inhibition---area in which the growth of bacteria is prevented or inhibited by an antibiotic or other substance; measurable

Koch's Postulates

  1. The same, specific pathogen must be identified in each host that has the disease.

  2. The pathogen must be isolated from a host and grown in a pure culture, one in which no other kinds of cells are present.

  3. The original disease must be produced in experiment hosts that are inoculated with the pathogen from the pure culture.

  4. The same pathogen must be isolated from the experimental hosts after the disease develops in them.

Bacteria Labs

How Common are Bacteria and How Quickly Do They Reproduce?(UP. 19-22)

observe the agar surface and count the number of colonies

  • without removing the cover

  • white, creamy, or yellow dots

  • white fuzzy colonies are molds

  • each colony represents what was one original cell placed on agar surface

  • record the numbers in the data table an share with your partner

Using Antibiotics to Stop Bacterial Growth (UP. 23-25)

look for zones of inhibitions surrounding the paper disks and measure the diameters in mm

  • do not open the petri dish

  • record the measurements in the data table and share with your partner

Thank you for reading,

see you tomorrow in class!


Next Scribe: ***Melissa***

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