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Cultures of a bacterial species were incubated on the shelf of a refrigerator (5°C), on a lab benchtop (25°C), on the shelf of a 37°C incubator, and on the shelf of a 50°C incubator. After incubation, there was no growth at 37°C or 50°C, slight growth on the benchtop, and abundant growth at refrigeration. What term could be used for this species?
A) halophile
B) mesophile
C) anaerobe
D) psychrophile - Correct Ans: ✔✔D
True or False: Irreversible cell damage is more likely to occur at low
rather than high temperatures. - Correct Ans: ✔✔False
True or False: Some microbes can grow in boiling water. - Correct
Ans: ✔✔True
True or False: Mesophiles typically have longer fatty acid tails and more saturated carbon-carbon bonds in their cytoplasmic tails
compared with thermophiles. - Correct Ans: ✔✔False
True or False: A bacterium such as a snow alga that is able to grow in
cold temperatures is called a psychrophile. - Correct Ans: ✔✔True
True or False: During the electron transport process, protons and electrons become physically separated in the cell membrane. -
Correct Ans: ✔✔True
True or False: If a substance is reduced, it gains electrons. - Correct
Ans: ✔✔True
True or False: The energy released from the hydrolysis of coenzyme
A is conserved in the synthesis of ATP. - Correct Ans: ✔✔True
True or False: In substrate-level phosphorylation, ATP storage is depleted during the steps in catabolism of the fermentable
compounds. - Correct Ans: ✔✔False
True or False: The proton motive force is most often generated by
splitting of H2. - Correct Ans: ✔✔False
Which metabolic strategy does NOT invoke the proton motive force for energy conservation?
A) aerobic catabolism
B) chemoorganotrophy
C) fermentation
E) None of the above - Correct Ans: ✔✔C
Predict how Pasteur's conclusions on spontaneous generation with swan flasks
would have changed if he worked with and maintained the flasks in a laminar flow
hood (where the air is sterile).
A) Sterilization of the swan flask solutions would not have been necessary to reject spontaneous generation. If he did sterilize the flasks, the spontaneous generation hypothesis would have been supported.
B) His incubation times would not have been sufficient to refute spontaneous generation.
C) Pasteur's flasks never would have putrefied, and the experiment would not have refuted spontaneous generation.
D) Viruses would have still been present, and his conclusion would
have been unchanged. - Correct Ans: ✔✔C
Of the structures listed below, which one is found in the outer most membrane of a Gram-negative cell?
A) Ribosomes
B) The peptidoglycan layer
C) The periplasm
D) LPS (lipopolysaccharide) layer - Correct Ans: ✔✔D
Gram-positive bacteria stain _____ with a Gram stain reaction because they have a __________ peptidoglycan layer than Gram- negative bacteria.
A) red / thinner
B) purple/ thinner
C) purple / thicker
D) red / thicker - Correct Ans: ✔✔C
Which of the following statement(s) is/are correct?
A) Flagella allow bacteria to glide
B) Flagella allow bacteria to swim
C) The directed movement of bacterial cells in response to a gradient of a chemical, is called chemotaxis
D) A and C are correct
E) B and C are correct - Correct Ans: ✔✔E
Electron microscopy has _________ ________ than light microscopy, because the wavelengths of electrons are much ___________ than the wavelength of visible light.
A) higher resolution/smaller
B) lower magnification/larger
During respiration electrons from the __________ of substrates are used to ________ a terminal electron acceptor that is either oxygen (aerobic respiration) or some other inorganic compound (anaerobic respiration).
A) reduction / oxidize
B) transport / degrade
C) oxidation / reduce
D) none of the above - Correct Ans: ✔✔C
Which intermediate compound(s) in the citric acid cycle is/are often used for biosynthetic pathways as well as carbon catabolism?
A) α-ketoglutarate
B) oxaloacetate
C) acetyl~CoA
D) All of the above
E) None of the above - Correct Ans: ✔✔D
Which pathway(s) are used to obtain anabolic intermediates:
A) Pentose phosphate pathway
B) Glycolysis
C) Citric acid cycle
D) All the above
E) None of the above - Correct Ans: ✔✔D
Which statement is FALSE?
A) Electron transport systems mediate transfer of electrons and conserve some of the energy released during transfer and use it to synthesize ATP
B) In electron transport systems, the electron carriers are membrane associated.
C) Fermentation requires a fully functional electron transport chain so that a proton gradient can be formed and drive the synthesis of ATP.
D) The proton motive force drives the conversion of ADP to ATP
through ATP synthase - Correct Ans: ✔✔C
By controlling the concentration of nutrients continuously added to a chemostat, cells can constantly be maintained at the
A) exponential growth phase.
B) stationary growth phase.
C) lag growth phase.
D) death growth phase. - Correct Ans: ✔✔A
A bacterial cell doubles every 30 minutes under given laboratory conditions. When a liquid broth is inoculated with 10 cells, how many cells will the culture contain after 4 hours?
A) Biofilms consist of bacterial cells that are embedded in an attached polysaccharide matrix and can affect human health, water distribution systems, and fuel storage
B) When a microbial population is growing exponentially, it means that the number of cells will double during a specific time interval
C) The time between inoculation of a bacterial culture and the beginning of growth is usually called the stationary phase
D) If a bacteria cell like Escherichia coli (10-12 g/cell) could grow without any restrictions, their mass could be that of planet earth (5 x 1027 g) in about two days time.
E) All of the above are false - Correct Ans: ✔✔C
Which statement is CORRECT:
A) Bacteria that are able to grow in humans and cause disease would be classified as thermophiles
B) Enumerating cells that clump together is challenging for direct counting by microscopy, measuring turbidity, and viability counts by spread plating.
C) The time interval required for the formation of two cells from one is called the growth rate
D) Smaller bacteria generally grow slower than larger ones due to a higher surface area-to-volume ratio.
E) All the above are correct - Correct Ans: ✔✔B
The yeast Saccharomyces cerevisiae belongs to the domain
__________ because its DNA is contained in a __________. - Correct
Ans: ✔✔Eukarya, nucleus
Which structure in or on bacteria prevents desiccation and
destruction by our immune system? - Correct Ans: ✔✔the capsule
A bacterium that can grow in your refrigerator but not at room temperature is called a __________. Its cell membrane contains more __________ fatty acids than the bacteria that thrive in your
gut. - Correct Ans: ✔✔psychrophile, unsaturated
Glycolysis consists of two stages: (i) the preparatory stage, where one molecule of glucose is __________ into __________ molecules of glyceraldehyde 3-phosphate, and 2 ATP are __________; (ii) the energy-conserving stage, where 4 ATP are produced in __________
phosphorylation, and __________ NADH are produced. - Correct
Ans: ✔✔split, two, used, substrate-level, two
List Robert Koch's four postulates that established a causative relationship between microbes like Mycobacterium tuberculosis and
the infectious disease they cause: - Correct Ans: ✔✔1 - the suspected pathogen must be present in all cases of the disease and absent from healthy animals.
2 - the suspected pathogen must be grown in pure culture
3 - cells from a pure culture of the suspected pathogen must cause disease in a healthy animal
D) developed the first rabies vaccine and treated thousands of
individuals - Correct Ans: ✔✔B
A Pasteur flask has a(n)
A) swan neck to prevent particulate matter from getting into the main body of the flask.
B) double neck so two substances may be added at the same time.
C) secondary opening at the base to allow for drainage.
D) inverted upper edge to prevent spillage while swirling. - Correct
Ans: ✔✔A
Bioremediation ________ by introducing pollutant-consuming microorganisms or specific nutrients that help microorganisms degrade pollutants.
A) accelerates the natural cleanup process
B) exploits genetic exchange mechanisms
C) invokes microbial evolution
D) uses chemotaxis of biodegrading microorganisms - Correct Ans:
✔✔A
An ecosystem includes ________ along with ________.
A) macroorganisms / microorganisms
B) living organisms / their chemical and physical environments
C) pathogenic organisms / non-pathogenic organisms
D) single celled organisms / multi-cellular organisms - Correct Ans:
✔✔B
A microbial cell's membrane is considered ________, because its internal constituents are
maintained within the cell. However, it also imports and exports other molecules in response to
its environment.
A) differential
B) microselective
C) rigid
D) semipermeable - Correct Ans: ✔✔D
Microorganisms play key roles in the cycling of important nutrients in plant nutrition, particularly those of...
A) carbon.
B) nitrogen.
C) sulfur.
D) carbon, nitrogen, and sulfur. - Correct Ans: ✔✔D
True or False: Most microorganisms are pathogenic. - Correct Ans:
✔✔False
True or False: All microorganisms require molecular oxygen to carry
on life functions. - Correct Ans: ✔✔False
True or False: The environment in which a microbial population lives
is its habitat. - Correct Ans: ✔✔True
True or False: Differentiation occurs only in multicellular organisms. -
Correct Ans: ✔✔False
True or False: The discipline of microbiology is intimately associated with biochemistry and genetics, because cells are both biochemical
catalysts and genetic coding devices. - Correct Ans: ✔✔True
True or False: Today, the enrichment culture technique developed over a century ago by Martinus Beijerinck remains a feasible approach to discovering bacteria capable of degrading pollutants. -
Correct Ans: ✔✔True
True or False: Smaller prokaryotic cells generally grow faster than
larger ones due to a higher surface-area-to volume ratio. - Correct
Ans: ✔✔True
Some archaea have unique phospholipids in their cytoplasmic membrane that
A) form a monolayer due to the presence of diglycerol tetraethers.
B) form a bilayer due to the presence of sterols.
C) form a stable ring structure due to the presence of crenarchaeol.
D) form a bilayer due to the presence of phosphatidylethanolamine. -
Correct Ans: ✔✔A
Light microscopy has _________ ________ than electron microscopy, because the wavelengths
of visible light are much ________ than the wavelength of electrons.
A) higher resolution/smaller
B) lower magnification/larger
C) lower resolution/larger
D) lower resolution/smaller - Correct Ans: ✔✔C
Using phase contrast microscopy on a wet mount of live cells, you observe motile bacilli moving rapidly and randomly through the field of view, changing directions after a brief tumble and taking off in a different direction. These cells are exhibiting ________ motility.
A) twitching
B) swimming
A) prokaryote.
B) bacterium.
C) archaeon.
D) eukaryote. - Correct Ans: ✔✔D
The rigid layer that is present in the cell walls of Bacteria that is primarily responsible for the strength of the wall is known as
A) pseudomurein.
B) S-layer.
C) cellulose.
D) peptidoglycan. - Correct Ans: ✔✔D
Some of the intestinal symptoms elicited by pathogens such as Salmonella, Shigella, and
Escherichia are due to the presence of
A) pseudomurein.
B) S-layers.
C) lipopolysaccharides.
D) peptidoglycan. - Correct Ans: ✔✔C
Based on the table of attributes given below, which of the following statements are FALSE about
the two organisms?
Characteristics - the first response after each characteristic is for bacterium A and the second is bacterium B
Endospore formation: yes no
Capsule: no yes
Pili: yes no
Flagella: no no
Morphology: bacillus bacillus
A) Bacterium A is more resistant to heat and ultraviolet light.
B) Bacterium B likely forms a slime layer better than Bacterium A.
C) Bacterium B is likely to exhibit motility.
D) Both bacteria may attach to surfaces. - Correct Ans: ✔✔C
All prokaryotes contain
A) a membrane-enclosed nucleus.
B) cytoplasm.
C) a nucleoid.
D) B and C
