Microbiology for Teachers
Sample Questions for Exam 4 (July 12)
MULTIPLE CHOICE: Circle the letter corresponding to the
one true answer for each question.
- Which statement about the biogeochemical cycles is
- Due to their metabolic flexibility, microbial
lithotrophs and phototrophs act as consumers more often than
they act as primary producers.
- The carbon, nitrogen and sulfur cycles, but not the iron
cycle, can all be completed in both anaerobic and aerobic
- Organotrophic microbes often act as decomposers in the
carbon cycle, but play no role in either the sulfur or the
- Which statement about environmental nitrogen metabolism
- The reactions involved in nitrogen fixation are
oxidative and require ATP; thus they require an aerobic
environment if they are to be carried out efficiently.
- During nitrogen-fixation, one N2 molecule is converted to
two NH3 molecules in three steps by an enzyme complex that
- Dissimilative nitrogen reactions are those through which
reduced forms of nitrogen are incorporated into organic
compounds such as amino acids.
MATCHING MULTIPLE CHOICE: Write the letter corresponding to
the BEST answer in the blank. You may need to use an answer
more than once within the set of questions indicated.
Answers to questions 3-4:
- anoxygenic phototrophs
- anaerobic organotrophs
- aerobic organotrophs
- oxygenic phototrophs
- aerobic lithotrophs
- Bacteria involved in the carbon cycle because they produce
cellulase, and are therefore able to partially degrade the glucose
storage molecule cellulose, are most likely to be _____.
- Bacteria that are active in the sulfur cycle because they
carry out the reaction sequence H2S
S under anaerobic conditions, are most likely to be _____.
TRUE-FALSE: If a statement is TRUE, write T
in the blank provided; if it is FALSE, write F in the
- _____ Soil is formed by a combination of physical, chemical
and biological processes by which parent material is fragmented
into successively smaller particles to form material that is
generally wet, anaerobic (but with aerobic microsites) and
eutrophic, is composed of both organic and inorganic components,
and contains a mixture of microorganisms.
- _____ One example of syntrophy is an interaction between two
separate species of microbes that allows one of them to carry out
an energetically unfavorable fermentation by providing
H2 to neighboring microbes, which use it in
energetically very favorable reactions.
Essay Question: Write your answer in the
- (5 pt) The newly-opened LazeDaze Clothes Washing Emporium,
which uses large amounts of phosphate-containing detergents, dumps
the water that has been used for washing clothes into a small pond
behind the establishment. As a result, the pond has become
completely clogged with cyanobacteria such as Anabaena, Nostoc,
and Cylindrospermum. Discuss why this nitrogen-poor pond is
supporting these cyanobacteria and not green algae, being certain
to explain how this condition is initiated and how it might be
© 1998-2002. John R. Stevenson. All Rights
questions and comments to:
R. Stevenson, Ph.D.
Department of Microbiology
Oxford, Ohio 45056
This document was last modified on Tuesday, 09-Jul-2002 18:30:58 EDT