Microbiology Exam #1-Fall 2010
Name_________________
Multiple choice. Choose the best answer (2 points each)
1. __D___ Which scientist is most responsible for finally laying the theory of
spontaneous
generation to rest? a) Joseph Lister; b) Robert Koch; c). Francesco Redi; d). Louis
Pasteur; e) Robert Woese
2. __A___ The surgeon who advocated using disinfectants on hands and in the air
prior to surgery was: a) Joseph Lister b) Ignaz Semmelweis c) Robert Koch
d) Louis Pasteur e) Antonie van Leeuwenhoek
3. __A___He conducted the first epidemiological study of disease and stopped a cholrea
outbreak in London by identifying its source as a town well: a) Snow; b) Semmelweiss;
c) Reidi; d) Pasteur; e) Koch.
4. __E___ Which of the following people did not make an important contribution to the
development or importance of sterile techniques in microbiology? a) Lister; b) Pasteur;
c) Spallazani d) Semmelweiss; e) van Leeuwenhoek
5. ___D__ Streptococcus mutans ,the bacterium that causes tooth decay, requires sucrose
to make this cell part that helps the bacterium to adhere to tooth enamel: a) flagella
b) periplasmic space c) basal body d) glycocalyx e) slime layer
6. __D___ A bacterial cell exhibiting chemotaxis probably has: a) fimbriae
b) capsule c) mesosomes d) flagella e) metachromatic granules
7. ___D__ Which structure protects bacteria from being phagocytized? a) slime
layer b) fimbriae c) cell membrane d) capsule e) all of the choices are
correct
8.__B___ Which of the following statements about endospores is false? a) they are
formed in response to adverse environmental conditions; b) they provide a means of
asexual reproduction for bacteria; c) they have a very low water content; d) the
mesosome is involved in their formation.
9. __C___ A bacterium with flagella arranged around the entire outside of the cell is
called: a) monotrichous. b) lophotrichous. c) peritrichous. d) amphitrichous. e) a spiral.
10._A____Mycoplasms are pleomorphic bacteria because they do not possess or contain:
a) peptidoglycan; b) flagella; c) pili; d) ribosomes; e) capsule.
11._C____Which of the following is most associated with procaryotic cells?
a) flagella with a 9+2 structure; b) sterols generally present in the cell membranes;
c) a nucleoid region d) 80s ribosomes; e) mitosis and meiosis.
12. __C___This cell part increases surface area for membrane-associated processes and is
involved in endospore formation: a) cell wall; b) pili; c) mesosome; d) cell envelope;
e) glycocalyx.
13.__C___The selective basis of most protein synthesis inhibiting antibiotics (the
antibiotics kill bacteria but not human cells) takes advantage of differences between
procaryotes and eucaryotes in this cell structure: a) cell wall; b) nucleoid; c) ribosomes;
d) DNA; e) cell membrane.
14.__A___The presence of this structure explains why penicillin will kill E.coli but not
Staph. aureus: a) LPS layer; b) periplasmic space; c) peptidoglycan; d) glycocalyx;
e) endospores.
15.___D__Bacterial cells exposed to this chemical would burst if they were placed in a
hypotonic environment: a) lysozyme; b) n-acetyl glucosamine; c) penicillin; d) a and c;
e) all of the above.
16.__A___Chemical substances found only in prokaryotic cells are present in this type of
cell structure: a) cell wall; b) flagella; c) inclusion; d) cell membrane; e) mesosome.
17.__D___Which of the following characteristics would be the best to utilize if you were
comparing bacteria and developing a phylogenetic scheme of classification for these
organisms: a) the enzymes that they produced; b) the products of fermentation of glucose
that they produced; c) morphological characteristics; d) G/C content; e) how they reacted
to various structural stains.
18.__B___After a gram staining procedure, a cell had a purple color. If you were
attempting to further identify this bacteria, in which volume of Bergey's Manual
(Systematic 1st Ed.) would you look for further information? a) Vol. I; b) Vol. II; c) Vol.
III; d) Vol. IV ; e) Vol. I & II; f) Vol. II & IV.
19.__B___The only group of bacteria that contains cholesterol in their cell membrane:
a) Rickettsia; b) Mycoplasms; c) Chlamydia; d) purple sulfur bacteria; e) Spirochetes.
20.__A___Obligate intracellular bacterial parasites that are the most common form of
sexually transmitted disease would be assigned to which volume of Bergey's Manual
(Systematic 1st Ed.)? a) I; b) II; c) III; d) IV.
21.___B__Helical shaped cells, many of which are parasites in vertebrates including the
causative agents of syphilis and Lyme disease, are members of this group: a) Rickettsia;
b) Spirochetes; c) Mycoplasms; d) Division Firmicutes; e) Volume II of Bergey's Manual
(Systematic 1st Ed.).
22.__E___Members of this group of bacteria were once (erroneously) thought to be
virus: a) Mycobacterium; b) Archaebacteria; c) members of the family
Enterobacteriaceae;
d) Mycoplasms; e) Rickettsia.
23.___A___Bacteria that caused food poisoning due to the release of lipid A molecules
from their cell wall would be located in which volume of Bergey’s Manual (Systematic
1st Ed.)? a) I; b) II; c) III; d) IV; e) cannot be determined from the information
provided.
24.__C___A unique group of bacteria that do not rely on the sun either directly or
indirectly can be found in this volume of Bergey’s Manual (Systematic 1st Ed.) : a) Vol I
b) Vol II c) Vol III d) Vol IV e) VOL V
25. (4 points each) Agree or disagree with the following statements. In either case, fully
defend your position.
A. The investigations of the validity of the theory of spontaneous generation were
essential in the development of microbiology into a legitimate science.
Agree-In order for micro to be a legit science, you had to be able to do controlled
experiments. This required a single variable being testes which was not possible if
you had microbial contaminants. Thus, we needed aseptic techniques to ensure
things didn’t get contaminated. Aseptic techniques were developed as a result of the
investigation into the validity of the theory of spontaneous generation.
B. It is significant that the majority of microbial pathogens are found associated with
biofilms.
Agree-If a pathogen is part of a biofilm, it is much harder to eradicate. Biofilms are
hard to remove. Bacteria that are part of biofilms are not as readily exposed to
oxygen, which is an important killing mechanism in some body defense systems.
Also, the biofilm can protect bacteria from antibiotics. Also, the fact that the biofilm
is a community of different species of bacteria makes it more likely that a species in
the biofilm may be naturally resistant to chemotherapeutic drugs.
C. Bergey’s 1st Ed. of Systematic Bacteriology is more phylogenetic than Bergey’s 8th
Ed. of Determinative Bacteriology.
Agree-Bergey’s 1st (Systematic) sometimes referred to as Bergey’s 9th is more
phylogenetic than Bergey’s 8th (Dete4rminative). It relies much more heavily on dna/rna
sequencing information than the 8th. The 8th makes heavy use of morphology and
biochemistry with some use of G/C ratios and serology.
D. Events in the periplasmic space are important in determining chemotactic behavior of
bacteria.
Agree-Chemotaxis is caused by a bacterium moving toward or away from a
chemical. Direction of movement is determined by the direction of flagellar rotation
(run/tumble). Receptors in the cell membrane and periplasmic space respond to
the chemicals and stimulate the flagella to either rotate clockwise (tumble) or
counterclockwise (run).
26. (8 points) Discuss and describe two different essential roles that microorganisms play
in ecological processes and 2 different essential roles they play in industrial processes.
I gave a long list in the first lectures about this. Any two different ecological examples
and any two different industrial examples would be fine (-several examples I gave were
types of industrial fermentation so they wouldn’t be different)
27. (20 points) A microbiologist performed the following staining tests on a bacterium
(species X) and came up with the following results.
Test
Result (+ or -)
Gram stain
Acid fast stain
Flagella stain
endospore stain
capsule
Sudan Black B stain
Iodine stain
Metachromatic granule (volutin) stain
(-)
(-)
(+)
(-)
(+)
(-)
(-)
(-)
Suppose that a chemical analysis was also done of species X (the same species
that the staining reactions are reported for above). From the list of possible substances
below, choose the letter corresponding to substance that, based upon the results of the
staining reactions given, would be present in species X and write them on the line below
(points will be deducted for failing to include a chemical that should be there as well as
including a chemical that shouldn't be there).
A=lipopolysaccharide
C=DNA binding proteins
E=lipid A
G=n-acetyl glucosamine
B=diamino pimelic acid
D=teichoic acid
F=mycolic acid
H=lysozyme
I=dipicolinic acid
K=polyphosphate
M=D-alanine
O=Poly B hydroxy butyric acid
R=n-acetyl muramic acid
T=glycogen
J= porins
L=flagellin
N=calcium ions
P=phospholipids
S=actin
U=peptidoglycan
List compounds present (by letter) here:
ABEGJLMPRSU
28. (8 points) Describe the characteristic and significance (ecological or medical) of
any 4 of the following groups of bacteria and indicate in which Volume of Bergey's
Manual of Systematic Bacteriology 1st. Edition they are found:
a) Rickettsia Vol I-obliagte intracellular parasites. Can’t metabolize glucose. Once
thought to be virus. Causative agents of Rocky Mountain spotted fever. Arthropod
vector.
b) Mycolpasms-Vol I-No cell wall; pleomorphic; sterols in cell membrane.
Causative agent of walking pneumonia.
c) Spirochetes VOl I-Helical shape-internal flagella, burrow into tissues, Syphilis
and Lyme disease.
d) Enterobacteriaceae Vol I-Family of bacteria including several genera of “gut
associated” bacteria. Includes several pathogen (plague) as well as many
opportunists. Indicator of fecal pollution of water.
e) Cyanobacteria Vol III-once called blue/green algae. Oxygenic photosynthesis.
Cyanine pigment to absorb sunlight. Often have gas vesicles. Some forms capable
of nonsymbiotic nitrogen fixation. Some filamentous forms with primitive cell
specialization (heterocysts)
f) green and purple sulfur bacteria VOl III-Anoxygenic photosynthesis. Break
down H2S and form elemental sulfur. Purple deposit sulfur granules in the cell and
green outside.
g) chemolithotropic bacteria Vol III-don’t rely on sunlight energy directly or
indirectly. “rock eaters” . Use inorganic C02 for carbon and oxidation of inorganic
molecules for energy. Only survivors when the sun burns out.