Ubiquity of Bacteria (Exercise 6)

Question 1

Using the number of colonies as an indicator, which habitat sampled by the class appears to contain more bacteria?

Answer 1

The samples that contained the most bacteria were all on people (hair, lips, etc).

Question 2

Why do you suppose this habitat contains such a high microbial count?

Answer 2

This habitat contained a high microbial count because people are giant nutrient sources!

Question 3

In what ways do the macroscopic features of bacterial colonies differ from that of molds?

Answer 3

Bacteria colonies are fairly well defined, but the mold colonies blended together and had more texture and color, which made it difficult (impossible) to count.

Question 4

Why is the level of contamination measured as number of colonies rather than size of colonies?

Answer 4

The size of the colonies vary, they could be big or small and would not provide an accurate count.

Question 5

Should one be concerned to find bacteria on the skin? How about molds?

Answer 5

Bacteria would not be concerning, but molds would be because molds are not usually on the skin.

Question 6

How can microbial levels be controlled on the skin? On surfaces in the environment? In the air?

Answer 6

Microbial levels on skin could be controlled with antibacterial soaps, levels could be controlled on surfaces using antibacterial wipes or bleach, and the air could be difficult to control but an air purifier could help.