Download 221_exam_1_2002

BioSc221/325 (WS2002)
Exam 1
Name ______________________________
Multiple choice. (1 point each) Choose the one best answer to each of the following questions.
____ Lipopolysaccharide (LPS) is associated with __ .
A. The outer membrane of Gram positive bacteria.
B. The cytoplasmic membrane of Gram positive bacteria.
C. The outer membrane of Gram negative bacteria.
D. The cytoplasmic membrane of Gram negative bacteria.
____ Which of the following are made up of eukaryotic cells?
A. Protozoa and animals
B. Bacteria and archaea
C. Bacteria and fungi
D. Archaea and fungi
____ Pseudopeptidoglycan is a characteristic of the walls of __.
A. Eubacterial prokaryotic cells.
B. Eukaryotic cells.
C. Archaean prokaryotic cells.
D. Eubacterial and Archaean prokaryotic cells.
____ When doing a colony count to determine the number of microorganisms in a sample __.
A. it is assumed that each colony arose from only one organism.
B. only viable cells are counted.
C. the medium must be suitable for colonial growth.
D. All of the above
____ In general, prokaryotic cells are __.
A. smaller than viruses
B. smaller than eukaryotic cells
C. larger than eukaryotic cells
D. about the same size a eukaryotic cells
____ Which of the following does not accurately describe the conditions early in Earth’s life prior to the appearance of
cyanobacteria?
A. Absence of oxygen in the atmosphere
B. Presence of an ozone layer.
C. Cataclysmic bombardments and volcanic activity.
D. Early appearance of prokaryotes.
____ Which of the following characteristics might enable thermophilic organisms to survive growth at high temperatures?
A. enzymes with fewer hydrogen bonds
B. osmoprotectants such as compatible solutes
C. high A+T content of chromosomal DNA
D. lipids rich in saturated fatty acids
____ The periplasm is a(n) __.
A. part of the outer cell membrane of gram negative organisms.
B. part of the inner cell membrane of gram negative organisms.
C. space between the cytoplasmic membrane and the outer membrane layers.
D. alternate name for the inner cell membrane of any prokaryotic cell.
____ Which of the following organisms are responsible for introducing molecular oxygen into the early Earth’s atmosphere?
A. algae
B. bryophytes
C. cyanobacteria
D. ferns
____ Bacterial cell which has lost its peptidoglycan layer but remains intact is called a(n)
A. lysozome
B. osmoplast
C. periplasm
D. protoplast
____ Proteins that form channels in the outer membranes of gram-negative bacteria.
A. bactoprenols
B. porins
C. transport proteins
D. lipoproteins
_____ Why is the 16S/18S rRNA gene used as a molecular "yardstick" for tracing the evolutionary relationship of living
organisms?
A. It is found in all living organisms.
B. The gene encoding rRNA is large, providing sufficient regions to see variations among almost all species.
C. Some regions of the rRNA gene are highly conserved and some are highly variable.
D. All of the above.
____ Which of the following proteins is not found in the cytoplasmic membrane of a bacterial cell?
A. Porins
B. Transport proteins
C. Proteins for synthesis of peptidoglycan
D. Proteins for energy generation
_____ __ is found only in the cell wall of gram-positive bacteria.
A. Porin
B. N-acetyltalosaminuronic acid
C. Lipopolysaccharide
D. Teichoic acid
_____ Which of the following used carbolic acid to disinfect surgical wounds and made surgery a much safer procedure due to
the decrease in patients dying of infected surgical wounds.
A. John Snow
B. Robert Koch
C. Joseph Lister
D. Ignaz Semmelweis
_____ Which of these statements about the generation of ATP by chemiosmosis is false?
A. Passing electrons through an electron transport chain generates proton motive force (PMF).
B. A proton motive force (PMF) includes a transmembrane concentration gradient of protons, with a high concentration of
protons on the outside of the cell.
C. A proton motive force (PMF) generates ATP from ADP as protons flow out of the cell through ATPase pores in the
membrane.
D. A proton motive force (PMF) can do other cellular work in addition to generating ATP.
E. In aerobic respiration, oxygen gas is the terminal electron acceptor of the electron transport chain.
____ Which of the following cell wall components elicits an inflammatory response in the human body?
A. pili
B. porins
C. capsule
D. lipopolysaccharide
____ When calculating the evolutionary distances between organisms based on their 16S/18S rRNA sequences, why do
scientists use "corrected" distances?
A. To compensate for sequencing errors.
B. To compensate for the size differences between 16S and 18S rRNA
C. To compensate for "back mutations" that occur at random, making the mutation frequency seem lower than expected.
D. To give computer programmers something to do.
_____ Which of these statements about the following reaction (which occurs during alcoholic fermentation) is true?
CH3-CHO + NADH 
Acetaldehyde
CH3-CH2OH + NAD+
Ethanol
A. Acetaldehyde is reduced to form ethanol.
B. NADH is oxidized to produce NAD +.
C. The reaction involves no net oxidation.
D. Acetaldehyde is more oxidized than ethanol.
E. All of the above are true.
_____ Insertion of a proton permeable pore into the cytoplasmic membrane of a bacterial cell will result in ___.
A. continued function of the electron transport chain but ATP will no longer be synthesized.
B. inhibition of both the electron transport chain and ATP synthesis.
C. inhibition of the electron transport chain but ATP synthesis will continue.
D. no effect on either the electron transport chain or ATP synthesis.
____ A fastidious organism is
A. oxygen sensitive
B. temperature sensitive
C. nutritionally demanding
D. atmospheric pressure sensitive
____ In chemiosmosis
A. OH- accumulates on the outside of the membrane while H+ accumulates on the inside.
B. OH- accumulates on the inside of the membrane while H+ accumulates on the outside.
C. both OH- and H+ accumulate on the inside of the membrane.
D. both OH- and H+ accumulate on the outside of the membrane.
____ Cocci arranged in "grape-like" clusters are known as __ .
A. streptococci
B. staphylococci
C. sarcinae
D. micrococci
____ The flagella found in bacteria __.
A. number the same in all bacteria.
B. are composed of carbohydrate.
C. are found only at one end of the cell.
D. are composed of protein.
Matching. (1 point each) Match the definition in the left column with the appropriate term in the right column. Note, not all
terms will be used.
____ The first to use an epidemiological approach to solving a disease outbreak (cholera).
____ Cocci arranged in chains.
____ Bacteria that remain blue after completion of the Gram stain procedure.
____ Another name for peptidoglycan
____ Fiber like structures on the surface of bacteria that aid in attachment to surfaces.
____ The energy source for the phosphotransferase system.
____ Amino acid found in the pentapeptide of the peptidoglycan of all gram-negative
bacteria.
____ Enzyme found in saliva that cleaves the -1,4 linkage of the peptidoglycan layer.
____ Molecules found in halophiles that protect them from the low water activity of their
environment.
____ Enzyme that protects bacteria from damage caused by hydrogen peroxide.
____ Identified the causative agents of the deadly diseases anthrax and tuberculosis
____ A culture technique in which conditions favor the growth of the desired type of
organism.
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
M.
N.
O.
P.
Q.
R.
S.
T.
U.
V.
W.
X.
Y.
Z.
ATP
Catalase
Compatible solutes
Diaminopimelic acid
Dipicolinic acid
Enrichment
Gram-negative
Gram-positive
Koch, Robert
Lipoteichoic acid
Lysine
Lysozyme
Murein
N-acetylmuramic acid
Pasteur, Louis
Periplasm
Peritrichous
Phosphoenolpyruvate
Pili
Porins
Protoplast
Sarcina
Semmelweis, Ignaz
Snow, John
Staphylococci
Streptococci
Short answer. (1 point each)
How does penicillin kill bacteria?
What is the advantage to the bacterial cell of using the phosphotransferase system as opposed to using a proton driven sugar
transport system?
What is the difference between a psychrophilic and a psychrotolerant organism?
Give one reason why microbiologists have failed to cultivate many of the microbes in the environment.
Name the three domains of life.
Some types of bacteria can exhibit "behavior" in which their movement is directed toward a particular substance or signal
referred to as "taxis". Other than chemotaxis, name one example of this "taxis" phenomenon.
What is a halophile?
Consider the electron tower figure to the right to answer the following questions.
E. coli can use molecular hydrogen as an energy source for respiration with electrons
from hydrogen entering the electron transport chain at the level of NADH. Either
oxygen or nitrate can function as a terminal electron acceptor but if both oxygen and
nitrate are available, they will only use oxygen for respiration. Why?
Why does aerobic respiration of glucose result in more ATP production than
fermentation of glucose to acetate?
Short Essay Questions. Please answer 3 of the following 4 short essay questions (5 points each - 5 bonus points possible for
answering all 4 questions)
Draw two bacterial growth curves that plot optical density (Absorbance at 600 nm) versus time and viable cell count vs. time
over a period of several days. Assume that each growth curve represents a culture that was inoculated with a bacterial starter
culture that was allowed to grow to saturation for several days. Be sure to label the axis, indicate the phases of the growth
curve and explain what is happening during each phase.
Describe the Gram Stain procedure and explain what is happening at each step and why. What would be the appearance of a
Gram negative bacterium such as Escherichia coli and a Gram positive bacterium such as Streptococcus mutans?
Describe the structure of the outer membrane of a Gram-negative bacterium in as much detail as possible. Include a
description of any key components of the outer membrane. A labeled picture is OK.
Describe the process of aerobic electron transport phosphorylation beginning with NADH as the primary electron donor.
Include all electron carriers and all coupling sites. Include a description of the relative redox potentials of the various electron
carriers.