Human Microbiota

A short quiz on the symbiotic relation between indigenous microbes and our bodies

You may want to read Bacterial Flora of Humans beforehand.

1. Indigenous human microbiota includes all of these* except:
A. algae     B. bacteria     C. archaea     D.fungi    E. viruses    F. protoctist  

2. Microbial sybionts: biofilms, bacterial colonies, etc live together with their human hosts and associate with them via
A. mutualism   B. commensalism   C. parasitism   D. all of the above

3. In or on a typical person, the number of microbes  is _______ mammalian cells
A. half that of   B. one third the number of   C. approximately the same as the number of
D. ten times that of

4. Quorum sensing means
A. activation of certain genes when a threshold density is reached in the microbiotic community
B. acting like a multicellular organism   C. possibility of inducing population wide changes
D. all of the above  E. none of the preceding

5.  True or False: Studying microbiota is principally done by culturing even though this technique excludes the majority of microbiological life.
A. True   B. False   C. Ambiguous

6. Organisms living in a biofilm community display __________ phenotypes, in other words observable traits, morphology, characteristics, and properties etc.
A. the same   B. similar   C. different

7.   Which statement is TRUE about Biofilms:
A. provide a single uniform microhabitat   B. display increased susceptibility to anti-microbiotic agents
C. are more vulnerable to host defensive systems   D. facilitate nutritional interactions between constituents.

8. The surface area of the mucous membranes (mucosa) in the combined intestinal and respiratory tracts is about _________ that of  all the skin that covers our bodies.
A. 10%     B. half     C. equal to     D. ten times   E. one hundred times

Even though microscopic, ecological laws apply. Which is which?

9. In an ecosystem, there will always be a nutrient such that its presence or lack will be the limiting factor for a particular organism.
A. Shelford's law of tolerance       B. Lieb's law of minimum

10.  Each microbe needs an intricate set of physicochemical conditions for growth or even survival. Outside of these ranges it can not exist.
A.Shelford's law of tolerance       B.Lieb's law of minimum

Bonus question What is the weight of all these indigious microbes each of us carries around with them?.

Suggested reading:
Michael Wilson's Bacteriology of Humans

Symbiotic Planet: A New Look At Evolution" by Lynn Margulis

* as far as this author can ascertain

Ce texte © 2008 Christopher Yukna - tous droits réservés

Christopher YUKNA
schools:Ecole des Mines IUT Fac de Droit
websites: The Business Emporium + Totally Unorthodox English + Science General
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e-mails: yukna(AT) or yuknachris(AT)


feel free to contact me with any questions