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Microbial metabolism/Growth and Nutrition

STUDY
PLAY
C
Which of the following statements concerning cellular metabolism is FALSE:

A) Energy obtained from nutrients or light is stored in the bonds of ATP
B) Enzymes are used in both catabolic and anabolic reactions
C) Macromolecules are converted into cell structures via catabolism
D) The goal of metabolism is reproduction of the organism
E) ATP is used in the formation of macromolecules
C
Anabolic reactions may be characterized as

A) exergonic.
B) breaking large molecules into smaller molecules.
C) forming large molecules from smaller molecules.
D) producing ATP.
E) breaking large molecules into smaller molecules to produce ATP.
D
Which of the following statements is FALSE concerning reduction reactions?

A) An electron acceptor gains an electron.
B) They are coupled with oxidation reactions.
C) They frequently involve electron carrier molecules.
D) An electron acceptor becomes more positively charged.
E) A molecule gains a hydrogen atom.
A
The molecule that an enzyme acts upon is known as its

A) substrate.
B) coenzyme.
C) apoenzyme.
D) holoenzyme.
E) catalyst.
B
Which of the following statements is FALSE concerning enzymes?

A) They are usually, but not always, proteins.
B) They function best at 37°C.
C) They can be denatured if the pH of their environment is too high or too low.
D) They form a temporary intermediate compound with a substrate.
E) They can be used to catalyze a chemical reaction over and over again.
B
Sulfanilamide is an antimicrobial drug that mimics the shape of an important substrate for a
particular bacterial enzyme, thereby inhibiting the enzyme. This type of inhibition is known as

A) allosteric inhibition.
B) competitive inhibition.
C) excitatory allosteric control.
D) noncompetitive inhibition.
E) feedback inhibition.
B
Which of the following produces NADPH?

A) the pentose phosphate pathway
B) the Entner-Doudoroff pathway
C) the Embden-Meyerhof pathway
D) both the Embden-Meyerhof and Entner-Doudoroff pathways
E) both the pentose phosphate and Entner-Doudoroff pathways
C
Which of the following statements is true concerning glycolysis?

A) It produces ATP by oxidative phosphorylation.
B) It occurs in the cell membranes of bacteria.
C) It both requires the input of ATP and produces ATP.
D) It is an alternative to fermentation.
E) It involves ribulose 5-phosphate as an intermediate.
A
Carbon dioxide is a by-product of which of the following?

A) the Krebs cycle
B) glycolysis
C) chemiosmosis
D) the pentose phosphate pathway
E) electron transport
E
Pyruvic acid is a product of

A) the Krebs cycle.
B) fermentation.
C) glycolysis.
D) the Entner-Doudoroff pathway.
Pyruvic acid is a product of
E) both glycolysis and the Entner-Doudoroff pathway.
D
All of the following are forms of oxidation EXCEPT

A) loss of an electron.
B) loss of hydrogen atom.
C) a dehydrogenation event.
D) substrate level phosphorylation.
E) gain of an oxygen atom and its electrons.
D
Which of the following can be the final electron receptor in anaerobic respiration in bacteria?

A) nitrate
B) pyruvic acid
C) sulfate
D) both nitrate and sulfate
E) both pyruvic acid and sulfate
C
Which of the following types of carrier molecules is NOT found in electron transport chains?

A) flavoproteins
B) metal-containing proteins
C) hemoglobin
D) cytochromes
E) ubiquinones
B
All of the following are associated with chemiosmosis EXCEPT

A) creation of a proton gradient.
B) beta-oxidation.
C) phosphorylation of 34 molecules of ADP.
D) oxidative phosphorylation.
E) ATP synthase.
D
Which of the following is a by-product of the catabolism of proteins?

A) lactic acid
B) acetyl-CoA
C) proteases
D) ammonia
E) carbon dioxide
A
What is the purpose of the light-dependent reactions of photosynthesis?

A) production of ATP and NADPH
B) production of oxygen
C) production of ATP and NADH
D) carbon fixation
E) regeneration of NAD+
D
Which of the following is (are) common to chemiosmosis and the light-dependent reactions
of photosynthesis?

A) reduction of NADP+
B) electron transport
C) a proton gradient
D) both electron transport and a proton gradient
E) electron transport, a proton gradient, and reduction of NADP+
C
Which of the following statements is FALSE concerning the Krebs cycle?

A) Oxaloacetic acid is regenerated.
B) It is also known as the tricarboxylic acid cycle.
C) Two molecules of acetyl-CoA generate more ATP after two cycles than a single molecule of glucose at the end of glycolysis.
D) The ATP generated is initially GTP.
E) NAD+ and FAD are reduced as a result.
B
How many ATP molecules can be produced from the NADH generated by the catabolism of a
molecule of glucose?

A) 34
B) 30
C) 38
D) 36
E) 4
E
Types of chlorophyll differ in

A) the amount of light they can absorb.
B) the amount of ATP they produce.
C) the number of electrons they release.
D) the amount of oxygen they utilize.
E) the wavelengths of light they absorb.
A
Membranes containing the photosystems necessary for photosynthesis are called

A) thylakoids.
B) grana.
C) stroma.
D) chlorophylls.
E) cytochromes.
D
Beta-oxidation of fatty acids produces a substrate of

A) the pentose phosphate pathway.
B) the Entner-Doudoroff pathway.
C) the Embden-Meyerhof pathway.
D) the Krebs cycle.
E) the Calvin-Benson cycle.
C
Which of the following is associated with the Calvin-Benson cycle?

A) acetyl-CoA
B) TMAO
C) RuBP
D) FADH2
E) PABA
D
What is the major product of the Calvin-Benson cycle that can then be used to form glucose?

A) CO2
B) ATP
C) RuBP
D) glyceraldehyde 3-phosphate
E) NADPH
E
Chemical reactions that can proceed toward either anabolism or catabolism are called

A) glycolytic.
B) light-independent.
C) synthetic.
D) cyclic.
E) amphibolic.
C
If a cell reverses the process of beta-oxidation, which of the following molecules will it make?

A) glycerol
B) amino acids
C) fatty acids
D) nucleotides
E) starch
A
When a cell forms an amino acid by adding an amine group derived from ammonia to a
precursor metabolite, this process is called

A) amination.
B) transamination.
C) reduction.
D) polymerization.
E) deamination.
B
The conversion of amino acids to carbohydrates is an example of

A) amination.
B) gluconeogenesis.
C) substrate-level phosphorylation.
D) beta-oxidation.
E) electron transport.
E
All of the following are aspects of a cell's ability to regulate its metabolism EXCEPT

A) use of the most energy-efficient energy source available.
B) synthesis or degradation of membrane transport proteins.
C) isolation of various enzymes within membranous organelles.
D) synthesis of a catabolic enzyme only when its substrate is available.
E) use of the same coenzymes for anabolic and catabolic reactions that share substrate molecules.
C
The metabolic processes called fermentation

A) produce substrates for the Krebs cycle.
B) are alternatives for the pentose phosphate pathway.
C) use an organic molecule as a final electron acceptor.
D) occur only when oxygen is readily available.
E) produce substrates for glycolysis.
E
Which of the following is a true statement concerning the structure and function of enzymes?

A) All enzymes bind to cofactors necessary for their function.
B) An apoenzyme is a combination of a cofactor bound to a holoenzyme.
C) The higher the temperature, the faster an enzyme will work.
D) Competitive inhibition of an enzyme occurs when an inhibitor binds to an allosteric site on the enzyme.
E) After an enzyme has catalyzed a reaction, it resumes its original shape and can interact with a new substrate molecule.
C
In which of the following stages of glycolysis is ATP made?

A) energy-investment stage
B) lysis stage
C) energy-conserving stage
D) both the energy-investment and the lysis stages
E) both the lysis and energy-conserving stages
D
Where is the most ATP generated for eukaryotic cells?

A) in the cytoplasmic membrane
B) in the cytosol
C) in the outer membrane of the mitochondria
D) in the mitochondrial matrix
E) on ribosomes
A
The conversion of pyruvic acid to acetyl-CoA can be described as ________, because a
molecule of CO2 is produced as a by-product.

A) decarboxylation
B) amination
C) respiration
D) oxidation
E) phosphorylation
A
Although glycolysis requires an input of ATP, this pathway results in a net gain of two ATP; therefore it is a(n) ________ pathway.
A) exergonic
B) endergonic
C) oxidative
D) reductive
E) neither exergonic nor endergonic
TRUE
Reactions that are both catabolic and anabolic are amphibolic.
TRUE
NAD+ and NADP+ are important examples of both coenzymes and electron carriers.
TRUE
Environmental changes can result in the inactivation of enzymes.
FALSE
As the concentration of substrate increases, the activity of the enzyme decreases
TRUE
Ribozymes are enzymes that cleave the subunits of the ribosome.
TRUE
During chemiosmosis, electrons are pumped across a membrane to produce ATP.
TRUE
Fermentation pathways provide a cell with an alternative way to regenerate NAD+ for glycolysis.
FALSE
Glucose is used as an energy source only when proteins and fats are not available.
TRUE
Essential amino acids are amino acids that cannot be synthesized by an organism and so must be provided as nutrients.
False
The pentose phosphate pathway generates all the necessary precursors for nucleotide biosynthesis.
ADP
ATP is produced by the phosphorylation of ________.
ENZYME
Another term for an organic catalyst is a(n) ________.
REDUCTION
A ________ reaction is one in which a molecule accepts an electron.
SATURATION
The ________ of an enzyme is reached when all active sites have bound substrate molecules.
ALLOSTERIC
When a noncompetitive inhibitor molecule binds to a(n) ________ on an enzyme, the shape of the active site changes so that substrate molecules can no longer bind.
PYRUVIC ACID
During glycolysis, glucose is converted to ________, a molecule that can be used in either fermentation or respiration pathways.
HYDROGEN
Electrons are transferred in the Krebs cycle in the form of ________ to NAD+ and FAD.
GRADIENT
The purpose of electron transport is to create a(n) ________ across a membrane that can then be used to make ATP.
ACCEPTOR
Anaerobic respiration involves the use of molecules other than oxygen as the ________ in an electron transport chain.
ACID
Laboratory fermentation tests often include a pH indicator because many bacteria produce ________ as they ferment carbohydrates.
TRANSAMINOSES
The ________ generate amino acids from carbohydrate precursors and glutamic acid.
photosystem
A(n) ________ is a collection of pigments such as chlorophyll that are used to absorb light in the light-dependent reactions of photosynthesis.
ANOXYGENIC
________ photosynthetic bacteria produce waste products such as sulfur as they obtain electrons for noncyclic photophosphorylation.
ENERGY
Enzymes increase the rate of reaction by lowering the ________.
D
All of the chemical reactions of the cell are called:
A. catabolism.
B. redox reactions.
C. phosphorylation.
D. metabolism
E. cellular respiration.
B
The breakdown of peptidoglycan to N-acetylmuramic acid, N-acetylglucosamine and peptides is an example of:
A. anabolism.
B. catabolism.
C. phosphorylation.
D. fermentation.
E. biosynthesis.
B
Enzymes are:
A. broken down in reactions that require energy input.
B. proteins that function as catalysts.
C. electron carrier molecules.
D. not needed for catabolic reactions.
E. All of the choices are correct.
A
Formation of peptide bonds between amino acids to build a polypeptide would be called:
A. anabolism.
B. phosphorylation.
C. fermentation.
D. exergonic.
E. glycolysis.
C
An apoenzyme:
A. is part of a simple enzyme.
B. is also called a coenzyme.
C. contains the active site.
D. is often an inorganic metal ion.
E. is an RNA molecule.
D
A holoenzyme is a combination of a protein and one or more substances called:
A. substrates.
B. apoenzymes.
C. catalysts.
D. cofactors.
E. None of the choices are correct.
A
Important components of coenzymes are:
A. vitamins.
B. metallic ions.
C. active sites.
D. substrates.
E. ribozymes.
E
Enzymes that can function at boiling water temperatures or other harsh conditions would be termed:
A. denatured.
B. ribozymes.
C. abzymes.
D. exoenzymes.
E. extremozymes.
D
Enzymes that are produced only when substrate is present are termed:
A. exoenzymes.
B. endoenzymes.
C. constitutive enzymes.
D. induced enzymes.
E. conjugated enzymes.
B
Enzymes that catalyze removing electrons from one substrate and adding electrons to another are called:
A. phosphotransferases.
B. oxidoreductases.
C. decarboxylases.
D. aminotransferases.
E. ligases.
A
When enzyme action stops due to a buildup of end product this control is called:
A. negative feedback.
B. competitive inhibition.
C. enzyme induction.
D. enzyme repression.
E. None of the choices are correct.
A
Most electron carriers are:
A. coenzymes.
B. enzymes.
C. hydrogens.
D. inorganic phosphate.
E. All of the choices are correct.
C
Exergonic reactions:
A. include synthesis of large carbohydrates.
B. only occur in heterotrophs.
C. occur during aerobic cellular respiration.
D. do not occur in anaerobic cellular respiration.
E. occur when ADP binds to inorganic phosphate to form ATP.
B
In the cell, energy released by electrons is often used to phosphorylate:
A. ATP.
B. ADP.
C. pyruvic acid.
D. oxygen.
E. NAD.
D
In addition to electrons, which of the following is also involved in electron transfer?
A. ADP
B. glucose
C. carbon
D. hydrogen protons
E. carbon dioxide
E
The most likely place where an exoenzyme participates in a chemical reaction is:
A. mitochondria.
B. within the cell membrane.
C. lysosomes.
D. cytoplasm.
E. outside of the cell.
A
All of the following are exoenzymes, except:
A. ATP synthase.
B. streptokinase.
C. penicillinase.
D. collagenase.
E. elastase.
D
All of the following pertain to glycolysis, except it:
A. occurs without oxygen.
B. ends with formation of pyruvic acid.
C. occurs during fermentation.
D. degrades glucose to CO2 and H2O.
E. involves reduction of NAD.
C
The formation of citric acid from oxaloacetic acid and an acetyl group begins:
A. glycolysis.
B. electron transport system.
C. Krebs cycle.
D. fermentation.
E. oxidative phosphorylation.
D
The step involving ATP, hexokinase, and the phosphorylation of glucose to glucose-6-phosphate is:
A. the final step of the Krebs cycle.
B. the first redox reaction of the electron transport system.
C. an example of oxidative phosphorylation.
D. an example of substrate-level phosphorylation.
E. an example of photophosphorylation
B
During aerobic cellular respiration, the final electron acceptor is:
A. pyruvic acid.
B. oxygen.
C. nitrate.
D. cytochrome c.
E. FAD.
E
Which of the following is NOT involved in the step that occurs between glycolysis and the TCA cycle?
A. reduction of NAD
B. decarboxylation of pyruvic acid
C. coenzyme A attaches to an acetyl group
D. dehydrogenation of pyruvic acid
E. pyruvic acid accepts electrons from NADH
A
In bacterial cells, the electron transport system is located in the:
A. cell membrane.
B. mitochondria.
C. chloroplasts.
D. ribosomes.
E. cytoplasm. A
B
In which pathway is the most NADH generated?
A. electron transport system
B. Krebs cycle
C. glycolysis
D. alcoholic fermentation
E. mixed acid fermentation
C
The reactions of fermentation function to produce _____ molecules for use in glycolysis.
A. pyruvic acid
B. ATP
C. NAD
D. NADH
E. glucose
A
During which of the phases of cellular respiration is the majority of ATP formed?
A. electron transport
B. Krebs cycle
C. glycolysis
D. processing of pyruvic acid for the Krebs cycle
E. All phases produce the same number of ATP molecules.
E
In bacterial cells, when glucose is completely oxidized by all the pathways of aerobic cellular respiration, how many ATP are generated?
A. 2 ATP
B. 3 ATP
C. 24 ATP
D. 36 ATP
E. 38 ATP
A
When glucose is broken down by glycolysis during bacterial fermentation, how many ATP are generated?
A. 2 ATP
B. 3 ATP
C. 24 ATP
D. 36 ATP
E. 38 ATP
B
Each NADH that enters the electron transport system gives rise to _____ ATP.
A. 2
B. 3
C. 24
D. 36
E. 38
C
As the electron transport carriers shuttle electrons, they actively pump _____ into the outer membrane compartment setting up a concentration gradient called the proton motive force.
A. ATP
B. phosphate
C. hydrogen ions
D. oxygen
E. NADH
C
Mixed acid fermentation:
A. produces butyric acid.
B. occurs in all bacteria.
C. produces acids plus CO2 and H2 gases.
D. is seen in Streptococcus and Lactobacillus.
E. also produces ethanol.
D
Anaerobic cellular respiration:
A. is also called fermentation.
B. only involves glycolysis.
C. does not generate ATP.
D. utilizes an electron transport system.
E. uses the same final electron acceptors as aerobic respiration.
A
Each FADH2 that enters the electron transport system gives rise to _____ ATP.
A. 2
B. 3
C. 24
D. 36
E. 38
B
In anaerobic respiration, all of the following can serve as the final electron acceptor, except:
A. nitrate.
B. oxygen.
C. sulfate.
D. nitrite.
E. None of the choices are correct
A
Enteric bacteria commonly occupy the human intestine and primarily produce:
A. CO2 and H2gases.
B. methane gas.
C. lactic acid.
D. alcohol.
E. butyric acid.
C
The process of alcoholic fermentation produces:
A. alcohol only.
B. alcohol and oxygen.
C. alcohol and carbon dioxide.
D. carbon dioxide and yeast.
E. yeast and oxygen.
D
Cyanide will cause rapid death in humans because it:
A. stops glycolysis.
B. stops the TCA cycle from turning.
C. stops the electron transport chain at coenzyme Q.
D. blocks cytochrome c oxidase.
E. inhibits the ATP synthase.
C
Why is cyanide harmless to some bacteria?
A. They break down the cyanide before it enters the electron transport chain.
B. They shut off the TCA cycle until the cyanide is diluted out of the cell.
C. They lack cytochrome c oxidase.
D. They don't allow cyanide to cross their cell wall.
E. Cyanide is deadly for all bacteria.
B
Fatty acids can be metabolized by entering:
A. glycolysis.
B. the TCA cycle.
C. the electron transport chain.
D. the phosphogluconate pathway.
E. lactic acid fermentation.
C
Enzymes that are regularly found in a cell are termed:
A. exoenzymes.
B. endoenzymes.
C. constitutive enzymes.
D. induced enzymes.
E. conjugated enzymes.
A
When amino acids are deaminated, they can be used as a source of:
A. glucose.
B. fat.
C. vitamins.
D. minerals.
E. carbon.
E
In eukaryotes, glycolysis takes place:
A. in the mitochondria.
B. in the endoplasmic reticulum.
C. in the cell membrane.
D. in the nucleus.
E. in the cytoplasm.
D
In eukaryotes, the Krebs cycle takes place:
A. in the nucleus.
B. in the endoplasmic reticulum.
C. in the cell membrane.
D. in the mitochondria.
E. in the cytoplasm
B
Photosynthesis is responsible for producing >50% of Earth's oxygen. During photosynthesis inorganic __ is fixed into organic compounds like___ without the help of sunlight.
A. H2O, Oxygen
B. CO2, C6H12O6
C. H2O, C6H12O6
D. CO2, Oxygen
E. All of the choices are correct
C
In the eukaryote, the respiratory chain is located in the ___, whereas the majority of ATP is produced by the respiratory chain in the _______ of a prokaryote.
A. Lysosome, flagella
B. Golgi body, mitochondria
C. Mitochondria, outer membrane space
D. Mitochondria, ribosome
E. SER, nucleus
FALSE
ATP molecules are catalysts that lower the activation energy needed to initiate a reaction.
True False
T
Hydrolysis reactions are catabolic reactions that use water to split the reactant into smaller subunits.
True False
T
ATP synthase is a complex enzyme needed for oxidative phosphorylation.
True False
F
Only yeast produces alcohol as a fermentation product.
True False
T
Facultative anaerobes can utilize aerobic cellular respiration when oxygen is present and fermentation when oxygen is in low supply.
True False
F
All aerobic bacterial species have identical electron acceptors in their electron transport systems.
True False
T
Glyceraldehyde-3-phosphate is an intermediary of glycolysis that can also be utilized in biosynthetic pathways.
True False
F
ATP is composed of deoxyribose, adenine, and 3-phosphate groups.
True False
T
Building block molecules for biosynthetic pathways come from the cell's catabolic pathways and from the environment.
True False
ENZYMES
The cell's metabolic reactions involve the participation of _____ that lower the activation energy needed for the initiation of a reaction.
________________________________________
CONDENSATION
_____ reactions are anabolic reactions involving ligases for synthesis and the release of one water molecule for each bond formed.
ELECTRON
FAD, NADP, NAD, and coenzyme A are all _____ carriers.
CYTOCHROMES
The redox carriers of the electron transport chain that have a tightly bound metal atom responsible for accepting and donating electrons are the _____.
________________________________________
2
Each FADH2 from the Kerbs cycle enters the electron transport system and gives rise to _____ ATP's.
AMPHIBOLIC
Metabolic pathways that are bidirectional are called _____ pathways.
ALLOSTERIC
_____ enzymes have an active site, and an additional regulatory site for non-substrate attachment.
IMV.C
____ testing can differentiate between bacterial species fermentation that produce mixed acids or 2, 3 butanediol.
AMINO
Amination is the addition of a/an _____ group to a carbon skeleton.
_______________________________________
B
In microbiology, the term growth usually refers to which of the following?
A) an increase in a microbe's size
B) an increase in the number of microbial cells
C) an increase in the amount of ATP produced
D) an increase in the number and size of microbial cells
E) an increase in the number and size of microbial cells and the amount of ATP produced
A
A cell that uses an organic carbon source and obtains energy from light would be called a
A) photoheterotroph.
B) lithoautotroph.
C) photoautotroph.
D) chemoheterotroph.
E) chemoautotroph.
D
A(n) ________ organism is one that requires oxygen for growth.
A) anaerobic
B) facultative anaerobic
C) aerotolerant
D) obligate aerobic
E) both aerotolerant and anaerobic
A
An aquatic microbe that can grow only at the surface of the water is probably which of the following?
A) a phototroph
B) a heterotroph
C) a chemotroph
D) a lithotroph
E) an anaerobe
C
Which of the following forms of oxygen is detoxified by the enzyme catalase?
A) singlet oxygen
B) hydroxyl radical
C) peroxide anion
D) superoxide radical
E) molecular oxygen
D
All of the following are used to protect organisms from the toxic by-products of oxygen EXCEPT
A) carotenoids.
B) superoxide dismutase.
C) peroxidase.
D) protease.
E) catalase.
E
A microbe that grows only at the bottom of a tube of thioglycollate medium is probably a(n)
A) obligate aerobe.
B) facultative anaerobe.
C) aerotolerant anaerobe.
D) microaerophile.
E) obligate anaerobe.
E
Nitrogen is a growth limiting nutrient for many organisms because
A) it is necessary for the biosynthesis of amino acids.
B) it is required for synthesis of nucleotides.
C) it is required for lipid synthesis.
D) only a small number of bacteria are able to extract it from the atmosphere.
E) only a few microbes can extract it from the atmosphere, but all organisms require it for amino acid and nucleotide synthesis.
A
All of the following are examples of growth factors used by microbes EXCEPT
A) heme.
B) selenium.
C) NADH.
D) vitamins.
E) amino acids.
E
At temperatures higher than the maximum growth temperature for an organism,
A) proteins are permanently denatured.
B) membranes become too fluid for proper function.
C) hydrogen bonds within molecules are broken.
D) hydrogen bonds are broken, and proteins are permanently denatured.
E) hydrogen bonds are broken, proteins are denatured, and membranes become too fluid.
C
Human pathogens are classified as
A) thermoduric.
B) thermophiles.
C) mesophiles.
D) hyperthermophiles.
E) psychrophiles.
A
The term barophile refers to which of the following growth requirements?
A) hydrostatic pressure
B) temperature
C) nitrogen source
D) pH
E) osmotic pressure
C
Which of the following organisms would be most likely to contaminate a jar of pickles?
A) a neutrophile
B) a thermophile
C) an acidophile
D) an obligate anaerobe
E) a mesophile
E
Organisms that can grow with or without oxygen present are
A) obligate aerobes.
B) facultative anaerobes.
C) aerotolerant anaerobes.
D) obligate anaerobes.
E) either facultative anaerobes or aerotolerant anaerobes.
C
A fastidious organism might be grown on which of the following types of media?
A) transport media
B) reducing media
C) enriched media
D) differential media
E) selective media
A
Obligate anaerobes may be cultured in the laboratory
A) in a reducing medium.
B) in a candle jar.
C) in standard Petri plates.
D) on blood agar plates.
E) on blood agar plates in a candle jar.
D
Joan wants to discover a microbe capable of degrading an environmental contaminant. Which of the following refers to the process she should use?
A) lyophilization
B) binary fission
C) quorum sensing
D) enrichment culture
E) nitrogen fixation
B
A microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the species is 1 hour, how long will it be before the culture contains more than 10,000 cells/ml?
A) 24 hours
B) 7 hours
C) 2 hours
D) 3 hours
E) 10 hours
D
An epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue cells in clinical samples from victims. The scientist wants to try to isolate the bacteria in the lab. What culture conditions are most likely to be successful?
A) culturing on blood agar plates
B) inoculation of EMB plates
C) incubation in a candle jar
D) inoculation of cell cultures
E) inoculation of a minimal medium broth
D
Which of the following measurement techniques would be useful to quantify a species of bacteria that is difficult to culture?
A) membrane filtration
B) viable plate counts
C) MPN
D) microscopic counts
E) metabolic activity
D
MacConkey agar plates represent ________ medium.
A) a minimal
B) a selective
C) a differential
D) both a differential and a selective
E) both a minimal and a selective
A
A Petroff-Hauser counting chamber is
A) a glass slide containing an etched grid for counting microbes directly using a microscope.
B) a device that counts cells as they interrupt an electrical current.
C) a device that measures the amount of light that passes through a culture.
D) an apparatus that traps bacterial cells on a membrane filter where they can be counted.
E) a device used to count numbers of bacterial colonies on a Petri plate.
B
Another term for the logarithmic growth of bacterial cells is
A) generation time.
B) exponential growth.
C) arithmetic growth.
D) absorbance.
E) binary fission.
E
A device that removes wastes and adds fresh medium to bacterial cultures in order to prolong the log phase of a culture is called a(n)
A) Coulter counter.
B) cytometer.
C) spectrophotometer.
D) pellicle.
E) chemostat.
C
A specimen of urine is determined to contain 30 bacterial cells per microliter. How many cells would be present in a milliliter?
A) 3
B) 300
C) 30,000
D) 3,000
E) 30 million
B
Which of the following is NOT a direct method for measuring the number of microbes in a sample?
A) viable plate counts
B) turbidity
C) Coulter counter
D) MPN
E) membrane filtration
B
During which growth phase are bacteria more susceptible to antimicrobial drugs?
A) lag phase
B) log phase
C) stationary phase
D) death phase
E) the susceptibility is the same for all phases
B
The use of salt and sugar in preserving various types of foods is an application of which of the following concepts?
A) nitrogen fixation
B) osmotic pressure
C) pH
D) hydrostatic pressure
E) quorum sensing
E
A clinical sample labeled as "sputum" was collected from
A) the skin.
B) the blood.
C) the central nervous system.
D) a piece of tissue.
E) the lungs.
C
The method of obtaining isolated cultures that utilizes surface area to dilute specimens is called
A) the pour-plate technique.
B) serial dilution.
C) the streak-plate technique.
D) transport media.
E) enrichment culturing.
D
________ are complex communities of various types of microbes that adhere to surfaces.
A) Aggregates
B) Colonies
C) Isolates
D) Biofilms
E) Media
B
A colony-forming unit is the number of cells
A) in a colony.
B) that produces one colony.
C) in a particular specimen.
D) that is in exponential phase in a culture.
E) that can be placed on a Petri plate.
A
All of the following ingredients might be found in complex media EXCEPT
A) hydrogen peroxide.
B) yeast extract.
C) blood.
D) soy extract.
E) milk proteins.
D
Sodium thioglycollate is associated with which of the following types of media?
A) transport media
B) differential media
C) complex media
D) reducing media
E) selective media
C
Which of the following quantification techniques can distinguish living cells from dead cells in a culture?
A) microscopic counts
B) dry weight
C) metabolic activity
D) a Coulter counter
E) turbidity
F
Obligate anaerobes have enzymes such as superoxide dismutase to protect them from the damaging effects of oxygen.
F
Nitrogen fixation is a process that occurs in all bacteria.
T
Thermoduric mesophiles are often responsible for spoilage of improperly canned foods.
T
An obligate halophile will burst if placed in freshwater.
F
The only effective way to store bacterial cultures for short periods of time is to arrest their metabolism by freezing.
T
Quorum sensing is a process by which bacteria respond to the density of other bacteria in their environment.
F
An obligate anaerobe can be cultured in a candle jar.
F
Agar is a useful compound in the microbiology lab because it is an excellent nutrient for bacteria.
T
A selective medium can be formulated either by including inhibitory chemical substances or by leaving out a single crucial nutrient.
T
In spectrophotometry, 40% light transmission is the same thing as 60% absorbance of light.
NITROGEN FIXATION
The conversion of nitrogen gas to ammonia is called ________.
HETEROTROPH
_______ are organisms that require organic sources of carbon and energy.
SUPEROXIDE
The ________ radical is formed during the incomplete reduction of O2 during electron transport in aerobes.
OPTIMUN
The ________ growth temperature is the temperature at which an organism exhibits the highest growth rate.
MESOPHILES
Bacteria that thrive at human body temperatures are classified as ________.
ALKINOPHILES
________ can survive in water up to pH 11.5.
CLINICAL SPECIMEN
A(n) ________ is a sample of microorganisms introduced into a growth medium.
PURE CULTURE
A(n) ________ is composed of cells that arise from a single colony.
AGAR
________ is a gelling agent derived from algae that is useful for creating solid growth media.
LAG
A sample placed into fresh medium is typically initially in the ________ phase of microbial growth.
GROWTH CURVE
A(n) ________ plots the number of organisms in a growing population over time.
FLOW CYTOMETRY
________ is a method of counting cells that have been stained or tagged with fluorescent dyes.
PELLICLE
A film of cells at the surface of a broth is called a(n) ________.
SPECTROPHOTOMETER
A(n) ________ can measure changes in the turbidity of a bacterial culture.
B
Microorganisms require large quantities of this nutrient for use in cell structure and metabolism:
A. element
B. macronutrient
C. water
D. growth factor
E. trace element
E
Microorganisms require small quantities of this nutrient for enzyme function and maintenance of protein structure:
A. element
B. macronutrient
C. water
D. growth factor
E. trace element
D
An organic nutrient that cannot be synthesized by the organism and must be provided is called a/an:
A. element.
B. macronutrient.
C. water.
D. growth factor.
E. trace element.
A
An important mineral ion of the cytochrome pigments of cellular respiration is:
A. iron.
B. zinc.
C. calcium.
D. magnesium.
E. potassium.
D
An important mineral ion that is a component of chloroplasts and stabilizer of membranes and ribosomes is:
A. iron.
B. zinc.
C. calcium.
D. magnesium.
E. potassium.
C
The term phototroph refers to an organism that:
A. uses CO2 for its carbon source.
B. must obtain organic compounds for its carbon needs.
C. gets energy from sunlight.
D. gets energy by oxidizing chemical compounds.
E. does not need a carbon source.
A
The term autotroph refers to an organism that:
A. uses CO2 for its carbon source.
B. must obtain organic compounds for its carbon needs.
C. gets energy from sunlight.
D. gets energy by oxidizing chemical compounds.
E. does not need a carbon source.
C
The term autotroph refers to an organism that:
A. uses CO2 for its carbon source.
B. must obtain organic compounds for its carbon needs.
C. gets energy from sunlight.
D. gets energy by oxidizing chemical compounds.
E. does not need a carbon source.
C
The term heterotroph refers to an organism that:
A. uses CO2 for its carbon source.
B. must obtain organic compounds for its carbon needs.
C. gets energy from sunlight.
D. gets energy by oxidizing chemical compounds.
E. does not need a carbon source.
D
The term chemotroph refers to an organism that:
A. uses CO2 for its carbon source.
B. must obtain organic compounds for its carbon needs.
C. gets energy from sunlight.
D. gets energy by oxidizing chemical compounds.
E. does not need a carbon source.
E
The methanogens, producers of methane gas, require environments that:
A. have sunlight.
B. are very acidic.
C. have abundant oxygen and CO2.
D. are extremely cold.
E. are anaerobic with hydrogen gas and CO2.
A
Organisms that feed on dead organisms for nutrients are called:
A. saprobes.
B. parasites.
C. autotrophs.
D. lithoautotrophs.
E. phototrophs.
C
The type of photosynthesis that does not produce oxygen:
A. occurs in cyanobacteria.
B. does not require CO2 as a reactant.
C. occurs in certain bacteria.
D. does not require sunlight.
E. occurs in algae and plants.
B
The movement of molecules from an area of high concentration to an area of lower concentration is called:
A. facilitated diffusion.
B. diffusion.
C. active transport.
D. osmosis.
E. endocytosis.
D
Diffusion of water through a semi-permeable membrane is called:
A. facilitated diffusion.
B. diffusion.
C. active transport.
D. osmosis.
E. endocytosis.
C
The movement of substances from lower to higher concentration across a semi-permeable membrane that must have a specific protein carrier and use energy is called:
A. facilitated diffusion.
B. diffusion.
C. active transport.
D. osmosis.
E. endocytosis.
A
The movement of substances from higher to lower concentration across a semi-permeable membrane that must have a specific protein carrier but no energy expenditure is called:
A. facilitated diffusion.
B. diffusion.
C. active transport.
D. osmosis.
E. endocytosis.
E
The use of energy by a cell to enclose a substance in its membrane by forming a vacuole and engulfing it is called:
A. facilitated diffusion.
B. diffusion.
C. active transport.
D. osmosis.
E. endocytosis.
D
When bacteria that are living in a freshwater stream moved to seawater, then what would happen?
A. It would be in a hypotonic solution.
B. It would gain water.
C. It would be in a isotonic solution.
D. It would shrivel.
E. None of the choices mentioned above are correct.
B
Which of the following microorganisms would find hypotonic conditions most detrimental?
A. bacteria
B. protozoa
C. fungi
D. algae
E. cyanobacteria
c
Which of the following require the cell to use ATP?
A. facilitated diffusion
B. diffusion
C. endocytosis
D. osmosis
E. None of the choices are correct.
A
Contractile vacuoles are:
A. used to expel excess water from cells.
B. found in bacterial cells.
C. important to certain organisms in hypertonic environments.
D. protein carriers in cell membranes.
E. None of the choices are correct.
D
Cultures of a bacterial species were incubated on the shelf of a refrigerator, out on a lab benchtop, on the shelf of a 37C incubator and on the shelf of a 50C incubator. After incubation, there was no growth at 37C and 50C, slight growth out on the benchtop, and abundant growth at refrigeration. What term could be used for this species?
A. halophile
B. mesophile
C. anaerobe
D. psychrophile
E. capnophile
C
Cultures of a bacterial species were incubated out on the incubator shelf, in an anaerobic jar and in a candle jar. After incubation there was moderate growth of cultures in the candle and anaerobic jars, but heavy growth of the culture on the incubator shelf. This species is a/an:
A. aerobe.
B. anaerobe.
C. facultative anaerobe.
D. microaerophile.
E. capnophile.
E
A microorganism that has an optimum growth temperature of 37C but can survive short exposure to high temperatures is called a/an:
A. extremophile.
B. thermophile.
C. psychrophile.
D. facultative psychrophile.
E. thermoduric.
D
An organism that grows slowly in the cold but has an optimum growth temperature of 32C is called a/an:
A. extremophile.
B. thermophile.
C. psychrophile.
D. facultative psychrophile.
E. thermoduric.
B
An organism with a temperature growth range of 45C to 60C would be called a/an:
A. extremophile.
B. thermophile.
C. psychrophile.
D. facultative psychrophile.
E. thermoduric.
A
All of the following could find a location in or on body tissues suitable for growth, except:
A. psychrophiles.
B. anaerobes.
C. facultative anaerobes.
D. mesophiles.
E. capnophiles.
B
A microorganism that does not have catalase or superoxide dismutase would find it difficult to live in an environment with:
A. carbon dioxide.
B. oxygen.
C. high salt.
D. temperatures above 37C.
E. high acidity.
D
Which of the following choice is true in case of a microaerophile?
A. It grows best in an anaerobic jar.
B. It grows with or without oxygen.
C. It needs normal atmospheric levels of oxygen.
D. It requires a small amount of oxygen but won't grow at normal atmospheric levels.
E. None of the choices are correct.
E
A halophile would grow best in:
A. acid pools.
B. fresh water ponds.
C. hot geyser springs.
D. arid, desert soil.
E. salt lakes.
D
The E. coli that normally live in the human large intestines and produce vitamin K that the body uses would be best termed a _____ relationship.
A. parasitic
B. saprobic
C. commensal
D. mutualistic
E. None of the choices are correct.
C
The time interval from parent cell to two new daughter cells is called the:
A. binary fission.
B. growth curve.
C. generation time.
D. death phase.
E. culture time.
C
The phase of the bacterial growth curve in which the rate of multiplication equals the rate of cell death is the:
A. lag phase.
B. log phase.
C. stationary phase.
D. death phase.
E. All of the choices are correct.
A
The phase of the bacterial growth curve in which newly inoculated cells are adjusting to their new environment, metabolizing but not growing is the:
A. lag phase.
B. log phase.
C. stationary phase.
D. death phase.
E. All of the choices are correct.
C
In the viable plate count method, a measured sample of a culture is evenly spread across an agar surface and incubated. Each _____ represents one _____ from the sample.
A. cell, cell
B. cell, colony
C. colony, cell
D. species, colony
E. generation, cell
A
The majority of organisms live or grow in habitats between:
A. pH 6 and 8.
B. pH 3 and 4.
C. pH 5 and 6.
D. pH 7 and 9.
E. pH 8 and 10.
E
An organism that grows best at a higher CO2 tension than is normally present in the atmosphere is a(n):
A. facultative anaerobe.
B. aerobe.
C. anaerobe.
D. aerotolerant anaerobe.
E. capnophile.
C
Barophiles are microorganisms able to tolerate:
A. a pH of 1 to 2.
B. high solute concentration.
C. high atmospheric pressure.
D. high osmotic pressure.
E. intense ultraviolet light.
D
Plant roots provide various growth factors for soil bacteria, and the bacteria help fertilize the plant by supplying it with minerals. This is an example of:
A. antagonism.
B. commensalism.
C. parasitism.
D. synergism.
E. mutalism.
B
The stage in a normal growth curve when cells reach the maximum rate of cell division is the:
A. lag phase.
B. log phase.
C. stationary phase.
D. death phase.
E. fast phase.
E
The decline in growth rate during the death phase is due to all of the following, except:
A. the depletion of nutrients.
B. the depletion of oxygen.
C. the excretion of biochemical pollutants.
D. the excretion of organic acids.
E. the decrease in temperature of the culture.
B
Which of the following methods of enumerating cells is the only one to detect live cells?
A. direct microscopic count
B. viable plate count
C. turbidity
D. coulter counter
E. flow cytometer
C
If a culture starts out with 1 cell and after 4 hours there are 64 cells, how many generations have occurred?
A. 4
B. 5
C. 6
D. 12
E. impossible to determine
C
You inoculate a culture into a test tube containing broth and take it out of the incubator the next day. You see the culture is growing equally throughout the broth. You conclude the culture must be:
A. aerobic.
B. anaerobic.
C. facultative anaerobe.
D. microaerophilic.
E. aerotolerant.
C
You inoculate a culture into a test tube containing broth and take it out of the incubator the next day. You see the culture is growing at the bottom of the tube. You conclude the culture must be:
A. aerobic.
B. anaerobic.
C. facultative anaerobe.
D. microaerophilic.
E. aerotolerant.
C
Facultative anaerobes usually possess:
A. catalase only.
B. superoxide dismutase only.
C. both catalase and superoxide dismutase.
D. neither catalase or superoxide dismutase.
E. alternative mechanisms for dealing with oxygen.
F
Most microorganisms on earth can only live and survive in habitats that are similar to human body conditions.
True False
F
Saprobes do not need a carbon source for growth and metabolism.
True False
T
The main reservoir of nitrogen is nitrogen gas from the earth's atmosphere.
True False
T
Lithoautotrophs use inorganic nutrients for carbon and energy sources.
True False
T
Facilitated diffusion and active transport require a carrier protein to mediate the movement across the plasma membrane.
True False
F
Bacteria have an average generation time of 24 hours.
True False
T
The time that it takes for a freshly inoculated agar culture to develop visible colonies is principally governed by that species generation time.
True False
T
In a commensal relationship, the commensal benefits but the cohabitant is neither harmed nor benefited.
True False
F
Transverse binary fission results in 4 daughter cells from 1 parent cell.
True False
F
After binary fission, daughter cells will differ genetically.
True False
T
A closed culture system is used to determine a population growth curve.
True False
T
The degree of turbidity in a culture correlates to the amount of cell growth.
True False
F
The direct cell count, using a cytometer, can quantitate viable cell numbers from a sample.
True False
F
Organisms depending on each for survival through time is coevoluion.
True False
F
All microbiota interactions with humans are harmful.
True False
EXTREMOPHILES
Microorganisms that live in severe habitats, such as very hot, acidic, or salty environments, are called _____.
________________________________________
PARASITES
Organisms called _____ live on or in the body of a host and cause some degree of harm.
_____________
PHAGOCYTOSIS
When whole cells or large molecules in solution are engulfed by a cell, this endocytosis is specifically termed _____.
________________________________________
CARRIER PROTEIN
Mediated transport of polar molecules and ions across the plasma membrane utilizes a _____ _____ that will bind to the substance effecting a conformational change that allows movement across the membrane.
____________________
AUTOTROPH
An organism that uses CO2 for its carbon needs would be called a/an _____.
________________________________________
HYPOTONIC
In _____ conditions, the cell wall will help prevent the cell from bursting.
________________________________________
SUPEROXIDE DISMUTASE, CATALASE
The toxic superoxide ion is converted to harmless oxygen by two enzymes: _____ and _____.
crenation
Cells that are exposed to hypertonic environments will exhibit ___________