Microbiology Quiz Answers

Which of the following techniques involves the use of three sets of five culture tubes each to estimate the number of bacteria in a sample? A. most probable number B. Coulter counter C. metabolic activity D. microscopic counts E. membrane filtration

A

Which of the microbial class listed is prokaryotic? A. archaea B. yeast C. virus D. Algae E. protozoa

A

Which of the following types of animal virus requires RNA-dependent RNA transcriptase to be replicated? A. retroviruses B. +ssRNA viruses C. -ssRNA viruses D. ssDNA viruses E. dsDNA viruses

C

Which of the following processes requires a carrier protein? A. diffusion B. active transport C. facilitated diffusion D. Both B and C are correct. E. A, B, and C are correct.

D

Which of the following staining procedures uses heat to drive the stain in? A. endospore stain B. acid-fast stain C. capsule stain D. Both A and B are correct. E. A, B, and C are correct.

D

Which of the following structure gives bacteria motility? A. fimbriae B. pilli C. glycocalyx D. flagella

D

Which of the following types of protozoa are bioluminescent? A. amoebae B. apicomplexans C. kinetoplastids D. dinoflagellates E. ciliates

D

Why is lysogeny advantageous to a bacteriophage? A. It speeds up the viral life cycle. B. It enables the bacteriophage to take over the cell. C. It allows the bacteriophage to infect cells it would not normally infect. D. The genetic material of the phage can be passed on to future generations of cells. E. It allows the bacteriophage to destroy the host cell's DNA.

D

The nucleoid A. contains the bacterial chromosome. B. is surrounded by a membrane. C. contains only RNA molecules. D. Both A and B are correct. E. A, B, and C are correct.

A

Vibrio cholera can cause hypovolemic shock by A. cAMP increase. B. cAMP decrease. C. inactivation of adenylate cyclase. D. intracellular increase of sodium. E. extracellular decrease of sodium.

A

Which of the following bacteria produce the most deadly bacterial toxins known? A. Clostridium botulinum B. Clostridium perfringens C. Clostridium difficile D. Clostridium tetani E. Corynebacterium

A

Which of the following classification methods relies on the morphology of organisms? A. physical characteristics B. serological tests C. analysis of nucleic acids D. phage typing E. biochemical tests

A

Which of the following would NOT be found as a subcomponent of a bacteriophage? A. icosahedral capsid B. envelope C. DNA D. tail fibers E. base plate

B

Which of the following is NOT true of endospores? A. Endospores are a reproductive structure. B. Endospores are dormant. C. Sporulation results in the degradation of the vegetative cell DNA. D. Endospores are resistant to boiling and chemicals.

A

Which of the following is the result of the action of cell wall inhibiting drugs? A. Cells become more susceptible to osmotic pressure. B. Cells cannot attach to their hosts. C. The replication of cells, including cancer cells, slows down. D. Ribosomes lose their function. E. The sterols in the cell wall become nonfunctional.

A

Which organism contains lipopolysaccharide? A. Gram positive B. Gram negative C. Gram positive and Gram negative D. neither

B

Which of the following must be removed from an mRNA molecule before it can be translated in eukaryotes? A. intron B. anticodon C. codon D. promoter E. exon

A

Which of the following scientists provided evidence in favor of the concept of spontaneous generation? A. Needham B. Redi C. Buchner D. Pasteur E. Spallanzani

A

Sulfanilimide 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 1) _______ A. competitive inhibition. B. excitatory allosteric control. C. allosteric inhibition. D. Both A and C are correct. E. A, B, and C are correct.

A

The accumulation of glucose inside a bacterial cell via phosphorylation of the molecule is an example of A. group translocation. B. osmosis. C. facilitated diffusion. D. plasmolysis. E. diffusion.

A

All of the following are characteristics of a genus name EXCEPT: A. it is usually an adjective. B. it is one of two names used to identify an organism. C. it is written before the specific epithet. D. it is either underlined or in italics. E. it is always capitalized.

A

All of the following are characteristics of noncyclic photophosphorylation EXCEPT: A. electrons return to the photosystem that generated them. B. it requires both photosystem I and II. C. Both ATP and NADPH are generated. D. Electrons are obtained from molecules such as water.

A

All of the following are characteristics of viruses EXCEPT: A. they are visible with a light microscope. B. they are composed of genetic material and protein. C. they are smaller than prokaryotic cells. D. they are acellular. E. they are obligatory parasites.

A

All of the following are true statements concerning glycolysis EXCEPT: A. It produces ATP by oxidative phosphorylation. B. It is a pathway common to both respiration and fermentation. C. It involves the conversion of a molecule of glucose into two molecules of pyruvic acid. D. It occurs in the cytoplasm of the cell. E. It uses, as well as produces, ATP.

A

All of the following statements are true for animal viruses and bacteriophage EXCEPT: A. Uncoating is required for bacteriophage. B. Animals take longer to replicate than bacteriophage. C. The bacteriophage genome can incorporate into the host chromosome. D. Animal viruses can enter via direct penetration. E. the attachment for bacteriophage and animal viruses is dependent upon chemical attraction.

A

B. anthracis producis a toxin responsible for: A. black lacerations called eschars. B. paralysis of skeletal muscles. C. Hemorragic colitis. D. None of the above. E. All of the above.

A

Carl Woese proposed the concept of the domain based on differences of which of the following cellular molecules? A. ribosomal RNA B. DNA C. proteins D. membrane lipids E. transfer RNA

A

Christian Gram devised a staining technique that divides all bacteria into two groups. A. True B. False

A

During the intracellular state, a virus exists solely as A. nucleic acid. B. protein. C. lipid. D. Both B and C are correct. E. Both A and C are correct.

A

If a microbiology lab technician left the safranin out of the Gram stain procedure, what would be the result? A. Gram-positive cells would be purple and Gram-negative cells would be colorless. B. All cells would be purple. C. Gram-positive cells would be pink and Gram-negative cells would be purple. D. All cells would be pink. E. Gram-positive cells would be colorless and Gram-negative cells would be pink.

A

In the presence of a decolorizing agent, Gram-negative cells lose the color of the primary stain. A. True B. False

A

Koch's postulates can only be used to prove the causes of infectious diseases. A. True B. False

A

Semisynthetic drugs represent all of the following improvements EXCEPT: A. they work faster. B. they are less susceptible to deactivation by bacterial enzymes. C. they are more readily absorbed in the intestines. D. they are more stable in the stomach. E. they are broader-spectrum in their action.

A

Sulfanilimide 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. competitive inhibition. B. excitatory allosteric control. C. allosteric inhibition. D. Both A and C are correct. E. A, B, and C are correct

A

Sister chromatids separate and move toward the poles of the cell during A. metaphase. B. prophase. C. anaphase. D. interphase. E. telophase

C

Which of the following is NOT true of inhibition? A. It is a clearing zone with no growth. B. The larger the zone the more resistant the organism is. C. It is measured as a diameter. D. It is measured after incubation. E. It is a result of diffusion of the drug out of the paper disk.

B

Which of the following is found at the 5' end of a DNA strand? A. a hydrogen bond B. a phosphate group C. a hydroxyl group D. histones E. a methyl group

B

Which of the following is the strongest base pair? A. adenine-thymine B. guanine-cytosine C. adenine-uracil D. Both B and C are correct. E. Both A and B are correct.

B

Which of the following molecules would be expected to cross the cytoplasmic membrane rapidly and without the use of transport proteins? A. ions B. small hydrophobic molecules C. large molecules D. Both B and C are correct. E. A, B, and C are correct.

B

Which of the following pairs is mismatched? A. plants: usually diploid B. fungi: usually diploid C. algae: usually haploid D. protozoa: usually haploid E. animals: usually diploid

B

Which of the following types of plasmids allows a bacterial cell to kill its competitors? A. virulence factors B. bacteriocin factors C. fertility factors D. cryptic plasmids E. resistance factors

B

Using a microscope, you observe an amoeba moving toward a food source. This is an example of A. cellular structure. B. responsiveness. C. reproduction. D. metabolism. E. growth.

B

Which of the following individuals discovered prions? A. Iwanowski B. Prusiner C. Stanley D. Rous E. Lacks

B

Which of the following is NOT a direct method for measuring the number of microbes in a sample? A. membrane filtration B. turbidity C. MPN D. viable plate counts E. Coulter counter

B

DNA helicases A. synthesize short DNA molecules important for the function of DNA polymerase. B. break hydrogen bonds between complementary nucleotides. C. seal gaps between DNA fragments. D. proofread DNA molecules. E. assist in recognition of promoters during transcription.

B

If the codon AAA is changed to AAG, it still codes for the amino acid lysine; this is an example of a A. nonsense mutation. B. silent mutation. C. frameshift mutation. D. gross mutation. E. missense mutation.

B

In microbiology, the term "growth" usually refers to which of the following? A. an increase in the amount of ATP produced B. an increase in the number of microbial cells C. an increase in a microbe's size D. Both A and B are correct. E. A, B, and C are correct.

B

Lipid-soluble molecules would be expected to cross the cytoplasmic membrane by which of the following processes? A. facilitated diffusion B. diffusion C. group translocation D. active transport E. osmosis

B

Membranes containing the photosystems necessary for photosynthesis are called A. cytochromes. B. thylakoids. C. chlorophylls. D. stroma. E. grana.

B

RNA polymerase and DNA polymerase differ from each other in all of the following ways EXCEPT: A. efficiency of proofreading. B. direction of polymerization. C. type of nucleotides used. D. dependence on helicase. E. speed.

B

The energy required for DNA replication comes from: A. the leading strand. B. triphosphate deoxyribonucleotides. C. DNA ligase. D. RNA primer. E. DNA polymerase.

B

The first eukaryote to have its entire genome sequenced was the fungus A. Cryptococcus. B. Saccharomyces. C. Candida albicans. D. Neurospora. E. Rhizopus.

B

The genome of which of the following types of animal virus can act directly as mRNA? A. dsRNA viruses B. +ssRNA viruses C. -ssRNA viruses D. retroviruses E. ssDNA viruses

B

The enzyme lysozyme is critical for which of the stages of a bacteriophage T4 life cycle? A. assembly B. entry C. entry and release D. synthesis E. attachment

C

Viroids infect A. bacteria. B. all organisms. C. plants. D. plants and animals. E. fungi.

C

Which of the following terms is NOT a component of bacterial flagella? A. flagellin B. basal body C. tubulin D. hook E. filament

C

A cell that uses an organic carbon source and obtains energy from light would be called a A. chemoautotroph. B. lithoautotroph. C. photoheterotroph. D. photoautotroph. E. chemoheterotroph.

C

All of the following are aspects of Pasteur's experiments to disprove spontaneous generation EXCEPT: A. the necks of the flasks he used were bent into an S shape. B. the flasks were incubated for very long periods of time. C. the flasks he used were sealed with corks. D. he boiled the infusions to kill any microbes present. E. the flasks were free of microbes until they were opened.

C

All of the following are associated with the packaging of eukaryotic chromosomes EXCEPT: A. histones. B. euchromatin. C. Okazaki fragments. D. heterochromatin. E. nucleosomes.

C

All of the following are characteristics of inducible operons EXCEPT: A. they are a way for bacterial cells to conserve energy. B. they are normally inactive. C. they are often involved in anabolic pathways. D. they are active in the presence of an inducer. E. they involve a repressor.

C

All of the following are targets of drugs that inhibit protein synthesis EXCEPT: A. the enzymatic site of the 50S ribosomal subunit. B. the shape of the 30S ribosomal subunit. C. interference with alanine-alanine bridges. D. movement of the ribosome from one codon to the next. E. the tRNA docking site.

C

All of the following statements concerning meiosis are true EXCEPT: A. Meiosis converts diploid cells to haploid cells. B. Genetic variety comes from crossing over in meiosis I. C. Tetrads are visible until anaphase II. D. Meiosis occurs in two stages. E. DNA replication occurs before meiosis begins.

C

An aligned pair of homologous chromosomes is called a A. coenocyte. B. spindle. C. tetrad. D. chromatid. E. gamete.

C

During translation, an mRNA codon will pass through which of the following sequences of tRNA binding sites on the ribosome? A. P site, A site, E site B. A site, E site, P site C. A site, P site, E site D. P site, E site, A site E. E site, P site, A site

C

Host specificty of a virus is due to A. differences in size between the virus and the host cell. B. particular genes that it shares with the infected cell. C. interactions between viral and cellular surface molecules. D. the presence of an envelope. E. the presence or absence of a cell wall on the host cell.

C

Host specificty of a virus is due to A. the presence of an envelope. B. the presence or absence of a cell wall on the host cell. C. interactions between viral and cellular surface molecules. D. differences in size between the virus and the host cell. E. particular genes that it shares with the infected cell.

C

How are prions different from all other known infectious agents? A. They cause neurological problems. B. They can be destroyed by incineration. C. They lack nucleic acid. D. They act as slow viruses. E. They cannot reproduce outside a cell.

C

In addition to coding for the amino acid methionine, what function does the codon AUG serve? A. termination signal B. marker for introns C. start signal D. recognition site for RNA polymerase E. causes "wobble"

C

Pasteur made all of the following observations concerning the fermentation of grape juice EXCEPT: A. yeast can grow with or without oxygen. B. yeast cells can grow and reproduce in grape juice. C. pasteurization kills yeast to prevent spoilage of grape juice. D. bacteria produce acid in grape juice. E. yeast can grow in sealed or open flasks of grape juice.

C

Saccharomyces cerevisiae is an example of which of the following types of microbes? A. viruses B. prokaryotes C. fungi D. protozoa E. algae

C

Semiconservative DNA replication means that A. the cell can proofread its newly synthesized DNA part of the time. B. nucleotides are constantly being recycled as cells make DNA. C. each daughter DNA molecule is composed of one original strand and one new strand. D. each strand of a double-stranded DNA molecule is replicated differently. E. the sequence of a DNA molecule is preserved as it is being replicated.

C

Viruses are primarily classified according to their A. number of chromosomes. B. shape. C. size. D. type of nucleic acid. E. type of life cycle.

D

All of the following are associated with nucleic acid structure EXCEPT: A. uracil. B. phosphate. C. hydrogen bonds. D. ionic bonds. E. ribose.

D

All of the following are used to protect organisms from the toxic by-products of oxygen EXCEPT: A. superoxide dismutase. B. peroxidase. C. catalase. D. protease. E. carotenoids.

D

Another term for the Kirby-Bauer test is the A. broth dilution test. B. minimum inhibitory concentration test. C. minimum bactericidal concentration test. D. diffusion susceptibility test. E. E test.

D

Because a codon is a particular combination of three nucleotides, there are __________ possible combinations of the nucleotides A, C, G, and T. A. 32 B. 16 C. 12 D. 64 E. 4

D

Chromatids are present in which of the following phases of mitosis? A. metaphase B. prophase C. telophase D. Both A and B are correct. E. A, B, and C are correct.

D

Lichens are in symbiosis with fungi and which of the following? A. green algae B. cyanobacteria C. euglenoids D. Both A and B are correct. E. Both A and C are correct.

D

Malachite green is used in which of the following staining procedures? A. Gram stain B. acid-fast stain C. flagellar stain D. endospore stain E. capsule stain

D

Merozoites are a result of A. conjugation. B. mitosis. C. meiosis. D. schizogony. E. crossing over.

D

Most of the fungi that spoil food belong to the division A. Rhodophyta. B. Basidiomycota. C. Zygomycota. D. Ascomycota. E. Deuteromycetes.

D

Plankton is composed of which of the following types of eukaryotic microbes? A. fungi B. algae C. protozoa D. Both B and C are correct. E. A, B, and C are correct.

D

Reverse transcriptase is associated with which of the following? A. +ssRNA viruses B. dsDNA viruses C. dsRNA viruses D. retroviruses E. -ssRNA viruses

D

The Gram stain works due to differences in the __________ of bacteria. A. capsules B. antigens C. genetic characteristics D. cell walls E. cell membranes

D

The fusion of two gametes produces a A. merozoite. B. schizont C. chromatid. D. zygote. E. centromere.

D

The most limited group of antimicrobial agents is the __________ drugs. A. antiprotozoan B. antifungal C. antihelminthic D. antiviral E. antibacterial

D

The outermost layer of a virion fulfills which of the following functions of the virus? A. protection B. recognition C. replication D. Both A and B are correct. E. A, B, and C are correct.

D

A bacterial cell moving toward light would be an example of A. negative phototaxis. B. negative chemotaxis. C. chemotaxis. D. positive chemotaxis. E. positive phototaxis.

E

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. 3 hours B. 24 hours C. 2 hours D. 10 hours E. 7 hours

E

Acidic dyes A. are used in negative staining. B. are negatively charged. C. work best in low pH environments. D. Both A and C are correct. E. A, B, and C are correct.

E

All of the following are common to both the Gram stain and the acid fast stain EXCEPT: A. a decolorizing agent and a mordant. B. primary stain. C. a decolorizing agent. D. counterstain. E. a mordant

E

At temperatures higher than the maximum growth temperature for an organism, A. proteins are permanently denatured. B. hydrogen bonds within molecules are broken. C. membranes become too fluid for proper function. D. Both A and B are correct. E. A, B, and C are correct.

E

Human pathogens are classified as A. thermoduric. B. hyperthermophiles. C. thermophiles. D. psychrophiles. E. mesophiles.

E

Protozoan cysts A. are reproductive structures. B. are a dormant stage. C. are resistant to environmental conditions. D. Both A and C are correct. E. Both B and C are correct.

E

Reverse transcriptase is associated with which of the following? A. +ssRNA viruses B. -ssRNA viruses C. dsDNA viruses D. dsRNA viruses E. retroviruses

E

The glycocalyx of a eukaryotic cell performs all of the following functions EXCEPT: A. cellular recognition and communication. B. protection against dehydration. C. strengthening the cell surface. D. anchoring cells to each other. E. transfer of genetic material between cells.

E

The microbial formation of alcohol from sugar is known as A. antisepsis. B. pasteurization. C. abiogenesis. D. metabolism. E. fermentation.

E

The molecule which an enzyme acts upon is known as its A. holoenzyme. B. coenzyme. C. catalyst. D. apoenzyme. E. substrate.

E

Which of the following are considered to be frameshift mutations? A. deletions B. inversions C. insertions D. Both A and B are correct. E. Both A and C are correct.

E

Which of the following is involved in translation? A. tRNA B. rRNA C. mRNA D. Both A and C are correct. E. A, B, and C are correct.

E

Obligate anaerobes have enzymes such as superoxide dismutase to protect them from the damaging effects of oxygen. A. True B. False

False

One of the symptoms caused by S. pneumoniae is a severe inflammation of the pericardium. A. TRUE B. FALSE

False

Prokaryotic cells are diploid. A. True B. False

False

Pseudomonas aeruginosa is sucesptible to most chemotherapeutic drugs. A. TRUE B. FALSE

False

Urea breakdown products decrease the pH of urine and gastric fluids. A. TRUE B. FALSE

False

Bdellovibrio infects gram-negative bacteria but it is not a human pathogen. A. TRUE B. FALSE

True

DNA, which is negatively charged, wraps around positively charged histones as part of the packaging of eukaryotic chromosomes. A. True B. False

True

P. vulgaris and mirabilis are the most common pathogens infecting long-term catheter users. A. TRUE B. FALSE

True

Streptococcus pneumoniae is an opportunistic pathogen. A. TRUE B. FALSE

True

The cholera toxin is a potent exotoxin composed of five identical B subunits and one A subunit. A. TRUE B. FALSE

True

The most common type of mutation is a point mutation. A. True B. False

True

Urea breakdown products increase the pH of urine and gastric fluids. A. TRUE B. FALSE

True

All of the following are forms of oxidation EXCEPT: A. loss of hydrogen atom. B. loss of an electron. C. substrate level phosphorylation. D. a dehydrogenation event. E. gaining an oxygen atom and its electrons.

c