Ch11 The Diversity Of Bacteria And Archaea Exam Questions

Nester’s Microbiology, 9e (Anderson)

Chapter 11 The Diversity of Bacteria and Archaea

1) It has been estimated that 99% of intestinal bacteria are

A) obligate aerobes.

B) facultative anaerobes.

C) obligate anaerobes.

D) facultative aerobes.

E) thermophiles.

2) The methanogens

A) are part of the domain Archaea AND appear only in aerobic environments.

B) oxidize hydrogen gas to produce methane AND appear only in aerobic environments.

C) use oxygen as a terminal electron acceptor AND appear only in aerobic environments.

D) use oxygen as a terminal electron acceptor AND oxidize hydrogen gas to produce methane.

E) are part of the domain Archaea AND oxidize hydrogen gas to produce methane.

3) Methanogens often grow in association with

A) nitrifying bacteria.

B) fermentative bacteria.

C) lithotrophic bacteria.

D) photosynthetic bacteria.

E) pathogenic bacteria.

4) Comparatively greater energy is released when

A) carbon dioxide is the final electron acceptor.

B) hydrogen is the final electron acceptor.

C) oxygen is the final electron acceptor.

D) nitrate is the final electron acceptor.

E) fermentation occurs.

5) Hydrogen sulfide

A) is produced when nitrate is used as terminal electron acceptor.

B) is produced by Desulfovibrio.

C) may react with iron to produce a deep red precipitate.

D) has a strong citrus smell.

E) All of the answer choices are correct.

6) Endospores

A) are a dormant form of a bacterium AND are formed by members of medically relevant groups of bacteria.

B) are a form of reproduction AND are formed by members of medically relevant groups of bacteria.

C) are a dormant form of a bacterium AND are involved in anaerobic respiration.

D) are formed by members of medically relevant groups of bacteria AND are involved in anaerobic respiration.

E) are a dormant form of a bacterium AND are found in any environmental bacteria.

7) Lactic acid bacteria such as Lactococcus

A) produce catalase.

B) are obligate fermenters.

C) require anaerobic environments.

D) use oxygen as a final electron acceptor.

E) are always pathogenic.

8) Streptococcus pyogenes

A) is alpha-hemolytic.

B) is gamma-hemolytic.

C) is beta-hemolytic.

D) may form endospores.

E) is alpha-hemolytic AND may form endospores.

9) The lactobacilli, in their role as normal microbiota of the vagina, help the vagina resist infection by contributing to

A) the neutrality of the vaginal mucus.

B) food for the resident vaginal microbiota.

C) acidity of the vagina.

D) fertility of the host.

E) a high vaginal pH.

10) Which of the following colonize the vagina during childbearing years?

A) Clostridium

B) Streptococci

C) Enterobacter

D) Lactobacilli

E) Clostridium AND lactobacilli

11) A particular characteristic of disease-causing Streptococcus is

A) catalase production.

B) beta-hemolysis.

C) lactic acid production.

D) growth at refrigerator temperatures.

E) endospore formation.

12) Propionibacterium

A) produces propionic acid AND is responsible for the holes in Swiss cheese.

B) produces propionic acid AND requires aerobic environments.

C) produces lactic acid AND is responsible for the holes in Swiss cheese.

D) is responsible for the holes in Swiss cheese AND requires aerobic environments.

E) produces lactic acid AND is a Gram-negative organism.

13) Which of the following microbes is(are) important to cheese-making?

A) lactic acid bacteria

B) Clostridium acetylbutylicum

C) Desulfovibrio

D) Propionibacterium

E) Lactic acid bacteria AND Propionibacterium

14) Clostridium, Lactobacillus, and Propionibacterium all

A) oxidize inorganic compounds AND use sulfur compounds as terminal electron acceptors.

B) oxidize organic compounds AND use sulfur compounds as terminal electron acceptors.

C) oxidize inorganic compounds AND use organic compounds as terminal electron acceptors.

D) oxidize organic compounds AND use organic compounds as terminal electron acceptors.

E) neutralize organic compounds AND use organic compounds as terminal electron acceptors.

15) Which of the following contains bacteriochlorophyll?

A) Bacillus, Chromatium, Thiospirillum

B) Staphylococcus, Thiospirillum, Thidictyon

C) Streptococcus,  Chromatium, Thidictyon

D) Escherichia, Chromatium, Thiospirillum

E) Chromatium, Thiospirillum, Thidictyon

16) Anoxygenic phototrophs

A) produce oxygen.

B) use water as a source of electrons.

C) use hydrogen sulfide or organic compounds as a source of electrons.

D) use the same form of chlorophyll found in terrestrial plants.

E) produce oxygen AND use the same form of chlorophyll found in terrestrial plants.

17) The purple sulfur and green sulfur bacteria

A) both use hydrogen sulfide as a source of electrons.

B) generate oxygen.

C) preferentially use organic molecules as an electron source.

D) both lack gas vesicles.

E) generate oxygen and lack gas vesicles.

18) The earliest oxygenic phototrophs are thought to be

A) purple sulfur bacteria.

B) green non-sulfur bacteria.

C) purple non-sulfur bacteria.

D) cyanobacteria.

E) cyanoarchaea.

19) Cyanobacteria

A) are a form of algae.

B) are prokaryotes.

C) use hydrogen sulfide as an electron source.

D) are eukaryotes.

E) contribute to global CO2 buildup.

20) Phycobiliproteins are

A) found in purple sulfur bacteria AND are used to gather wavelengths of light that are not well absorbed by chlorophyll.

B) found in cyanobacteria AND are used to reduce hydrogen sulfide.

C) used to gather wavelengths of light that are not well absorbed by chlorophyll AND are used to reduce hydrogen sulfide.

D) are used to reduce hydrogen sulfide AND are found in purple sulfur bacteria.

E) found in cyanobacteria AND used to gather wavelengths of light that are not well absorbed by chlorophyll.

21) The genus of bacteria that is able to fix nitrogen and form heterocysts is

A) Pseudomonas.

B) Anabaena.

C) Escherichia.

D) Vibrio.

E) Streptococcus.

22) Heterocysts

A) are found in nitrogen-fixing cyanobacteria AND produce catalase.

B) are found in nitrogen-fixing cyanobacteria AND are used to protect nitrogenase.

C) are used to protect nitrogenase AND generate oxygen.

D) produce catalase AND are found in nitrogen-fixing cyanobacteria.

E) are found in nitrogen-fixing cyanobacteria AND generate oxygen.

23) Purple sulfur bacteria and filamentous sulfur-oxidizers both

A) accumulate sulfur as intracellular granules.

B) fix nitrogen.

C) produce oxygen from carbon dioxide.

D) use gliding motility.

E) have gas vesicles.

24) Sulfuric acid is

A) involved in bioleaching AND produced by Lactobacillus.

B) produced by unicellular sulfur-oxidizers AND is a result of reduction of metal sulfides.

C) involved in bioleaching AND produced by unicellular sulfur-oxidizers.

D) a result of reduction of metal sulfides AND involved in bioleaching.

E) is a result of reduction of metal sulfides AND is produced by Lactobacillus.

25) The conversion of ammonium to nitrate could be accomplished by the presence of

A) Nitrosomonas alone.

B) Nitrobacter alone.

C) Anabaena alone.

D) Nitrosomonas and Nitrobacter.

E) Nitrosomonas, Nitrobacter, and Anabaena.

26) The Gram-positive rod that is also acid-fast and is a human pathogen is

A) Corynebacterium diphtheria.

B) Mycobacterium tuberculosis.

C) Streptococcus pyogenes.

D) Listeria monocytogenes.

E) Mycoplasma pneumoniae.

27) Which organism(s) is/are acid-fast?

A) Nocardia AND Mycobacterium

B) Pseudomonas AND Escherichia

C) Escherichia AND Mycobacterium

D) Mycobacterium AND Pseudomonas

E) Nocardia AND Pseudomonas

28) Which of the following organisms is the causative agent of Hansen's disease (leprosy)?

A) Pseudomonas aeruginosa

B) Mycobacterium avium

C) Mycobacterium leprae

D) Mycobacterium smegmatis

E) Mycoplasma leprae

29) Pseudomonas species

A) are resistant to many disinfectants and antimicrobials AND do not contain plasmids.

B) are mostly harmless except for the opportunistic P. aeruginosa AND do not contain plasmids.

C) require nutrient-rich environments AND are mostly harmless except for the opportunistic P. aeruginosa.

D) require nutrient-rich environments AND do not contain plasmids.

E) are resistant to many disinfectants and antimicrobials AND are mostly harmless except for the opportunistic P. aeruginosa.

30) Thermus and Deinococcus

A) are both thermophilic.

B) are both radiation resistant.

C) both serve as the source of Taq polymerase.

D) are both Gram-positive.

E) survive in extreme environments.

31) Which of the following statements about members of the family Enterobacteriaceae is NOT true?

A) It includes E. coli, Enterobacter, Salmonella, and Shigella.

B) It includes many medically relevant bacteria.

C) Members only reside in the intestinal tract of humans.

D) Members are facultative anaerobes.

E) All of the choices are correct.

32) Coliforms

A) are an informal grouping of enterics.

B) ferment lactose.

C) include E. coli.

D) are used as indicators of fecal contamination.

E) All of the choices are correct.

33) Bacteria that may form endospores include

A) E. coli AND Bacillus.

B) Pseudomonas AND Micrococcus.

C) Clostridium AND Bacillus.

D) Enterococcus AND Deinococcus.

E) Clostridium AND Deinococcus.

34) Which of the following structures would be the best choice as a biological indicator to test autoclave operations?

A) Cysts formed by Azotobacter species.

B) Microcysts within the fruiting bodies of myxobacteria.

C) Dormant spores in the conidia of Streptomyces species.

D) Endospores formed by Geobacillus stearothermophilus.

E) Sulfur granules produced by Thiothrix species.

35) Azotobacter

A) forms endospores.

B) fixes nitrogen.

C) fixes carbon dioxide.

D) is used as an indicator of fecal pollution.

E) is a hyperthermophile.

36) Streptomyces

A) resemble fungi in their pattern of growth AND produce a number of antibiotics.

B) resemble fungi in their pattern of growth AND produce a characteristic blue-green pigment.

C) produce a number of antibiotics AND form endospores.

D) produce a characteristic blue-green pigment AND form endospores.

E) form endospores AND resemble fungi in their pattern of growth.

37) Complex structures called fruiting bodies are a characteristic of

A) Clostridia.

B) Streptomyces.

C) lactic acid bacteria.

D) myxobacteria.

E) bacilli.

38) Agrobacterium species

A) contain the Ti plasmid that modifies the growth of plant tissue.

B) produce antibiotics.

C) infect animal cells.

D) resemble fungus.

E) are a group of Gram-negative rod-shaped bacteria that often fix nitrogen.

39) Rhizobium species

A) resemble fungi.

B) fix nitrogen inside nodules on the roots of legumes.

C) produce antibiotics inside nodules on the roots of legumes.

D) produce a gall in plants.

E) contain the Ti plasmid that modifies the growth of plant tissue.

40) Which causes uncontrolled growth of plant tissue, resulting in a tumor?

A) Bacillus anthracis

B) Rhizobium

C) Yersinia pestis

D) Agrobacterium

E) Cyanobacteria

41) Sphaerotilus and Leptothrix are examples of

A) purple sulfur bacteria.

B) Enterobacteriaceae.

C) sheathed bacteria.

D) green non-sulfur bacteria.

E) prosthecate bacteria.

42) Swarmer cells are

A) formed by Myxobacteria.

B) formed by sheathed bacteria.

C) also known as coliforms.

D) part of the green non-sulfur bacteria.

E) used in sewage treatment.

43) Bdellovibrio species

A) prey on other bacteria.

B) are parasites of plants.

C) may fix nitrogen.

D) are photosynthetic.

E) are filamentous.

44) Luminescence

A) is catalyzed by luciferase.

B) may be controlled by quorum sensing.

C) may be produced by bacteria.

D) All of the choices are correct.

E) None of the choices is correct.

45) Movement of spirochetes occurs by means of structures called

A) cilia.

B) flagella.

C) endoflagella.

D) pili.

E) microvilli.

46) Many spirochetes are difficult to cultivate, so their classification is based on their

A) morphology AND ability to cause disease.

B) number of flagella AND morphology.

C) pattern of pili AND flexible cell wall.

D) number of chromosomes AND pattern of flagella.

E) ability to cause disease AND pattern of flagella.

47) Helicobacter pylori

A) inhabits squid ink sacs.

B) causes crown gall in plants.

C) inhabits the stomach.

D) has axonemes.

E) produces luminescence.

48) Organisms that typically produce colonies with a fried egg appearance are the

A) Mycobacteria.

B) Mycoplasmas.

C) Actinomyces.

D) Chlamydia.

E) Escherichia.

49) Which of the following about Mycoplasma is FALSE?

A) They lack peptidoglycan.

B) They are the smallest free-living organisms.

C) They have sterols in their membranes.

D) They are killed by penicillin.

E) They are pleomorphic.

50) Treponema and Borrelia

A) are luminescent.

B) are endosymbionts.

C) are both easily grown on artificial media.

D) are spirochetes.

E) are never motile.

51) Which of the following is/are obligate intracellular parasites?

A) Chlamydia and Rickettsia

B) E. coli and Pseudomonas

C) Mycoplasma and E. coli

D) Treponema and Chlamydia

E) Rickettsia, Chlamydia and Pseudomonas

52) Reticulate and elementary bodies are two forms in the life cycle of

A) Mycoplasma.

B) Caulobacter.

C) Chlamydia.

D) Myxobacteria.

E) Treponema.

53) Wolbachia are found only in

A) hot springs.

B) plants.

C) mammals.

D) arthropods.

E) marine water.

54) The Euryarchaeota includes all

A) known extreme acidophiles.

B) the bacteria.

C) known methanogens.

D) green sulfur bacteria.

E) intracellular parasites.

55) Members of the Archaea typically thrive in conditions of excessive

A) heat.

B) acidity.

C) alkalinity.

D) salinity.

E) All of the choices are correct.

56) Archaea are typically found living in extreme environments. An exception to this are the

A) sulfur-oxidizing archaea.

B) sulfur-reducing archaea.

C) methanogens.

D) sulfur-oxidizing archaea AND sulfur-reducing archaea.

E) methanogens AND sulfur-reducing archaea.

57) The skin and oral cavity may have anaerobic microenvironments.

58) Lactic acid bacteria such as Streptococcus are obligate fermenters that can exist in an aerobic environment due to their use of catalase to mitigate the presence of oxygen.

59) Bacteria and Archaea both have members that use sulfur compounds as a terminal electron acceptor.

60) Anoxygenic phototrophs grow photosynthetically only under aerobic conditions.

61) Obligate aerobes may transform energy via fermentation.

62) The most medically relevant species of Pseudomonas is P. aeruginosa.

63) Streptomyces produce a number of antibiotics.

64) Rhizobium is considered an endosymbiont with plants.

65) Chlamydia occurs in two forms, a reticulate body and an elementary body.

66) Approximately 99% of the microbes in the intestines are obligate anaerobes. We have plenty of blood vessels that can bring oxygen to the tissues of the intestines. Why would there be obligate anaerobes within these areas?

A) The bacteria in the intestines are protected from exposure to the oxygen in the tissues by the lining of the intestines.

B) The bacteria consume all the oxygen in the tissue areas brought by the blood vessels, creating an anaerobic environment.

C) The inside space of the intestines is highly anaerobic. It is deep inside the body where oxygen cannot reach and it is not supplied with blood.

D) The aerobic microbes are outcompeted for nutrients in these areas by the anaerobic microbes.

E) The inside space of the intestines is highly anaerobic. It is deep inside the body where carbon dioxide accumulates.

67) Relatively little is known about many obligate anaerobes. Why might this be so?

A) There are far more obligate aerobes in any environment, so it is much easier to study them.

B) It is difficult to provide the right atmospheric environment to cultivate obligate anaerobes, so it's been harder to study them.

C) Only obligate aerobes cause disease, so we have had little reason to study obligate anaerobes.

D) The majority of obligate anaerobes are very nutritionally fastidious, which makes it difficult to study them.

E) It is difficult to provide the right temperature to cultivate obligate anaerobes, so it's been harder to study them.

68) How do anoxygenic phototrophs benefit from having accessory pigments that allow light to be harvested at deeper areas of a moist or aquatic environment?

A) Accessory pigments allows even anaerobic microbes to carry out photosynthesis, as they can harvest light energy in the deeper areas where oxygen won't be present.

B) The cells can use wavelengths of light that have not been absorbed by the photosynthetic organisms closer to the surface of the water.

C) These organisms don't have to compete with other cells that use oxygen in the upper levels for the scarce nutrients in the aquatic environment.

D) This allows even anaerobic microbes to conduct photosynthesis, as they can harvest light energy in the deeper areas where oxygen won't be present AND can use wavelengths of light not absorbed by the photosynthetic organisms closer to the surface of the fluid.

E) This allows even anaerobic microbes to conduct photosynthesis, as they can harvest light energy in the deeper areas where oxygen won't be present, use wavelengths of light not absorbed by the photosynthetic organisms closer to the surface of the water; AND don't have to compete with other cells that use oxygen in the upper levels for the scarce nutrients in the fluid environment.

69) How could heavily fertilized lawns contribute to cyanobacterial blooms in lakes and oceans?

A) Run-off from the lawns will get into the water system, leading to large amounts of nitrogen that can be used by cyanobacteria in water systems.

B) Nutrient-rich grass will be mowed down, with grass clipping bits eventually washing into sewer systems and into larger bodies of water. These grass clippings will serve as a nutrient source for cyanobacteria, leading to blooms.

C) Large amounts of fertilizer will lead to excessive production of greenhouse gases (like CO2) from grass in lawns. Excessive CO2 production will lead to large blooms of cyanobacteria in water systems.

D) Fertilizers contains compounds that encourage the production of bacteriochlorophylls; after rain, fertilizers get into water and are used by cyanobacteria. 

E) They won't—the two systems are completely unrelated. How could grass in lawns contribute to effects in lakes and oceans?

70) The genomes of free-living spirochetes are larger than those living in animal hosts. Why might this be so?

A) Free-living spirochetes will need genes for additional proteins to synthesize or obtain their own food from the environment. Parasitic spirochetes obtain nutrients from the animal host.

B) The spirochetes in animal hosts are different species entirely. As different species, they would naturally have smaller genomes.

C) A smaller genome implies simplicity—the spirochetes living in animal hosts have fewer needs, so they need fewer genes.

D) It isn't so—all spirochetes would have the same size genomes, since they're all the same species of microbe.

E) Parasitic spirochetes are smaller than free-living spirochetes. Because of this, their genomes are also smaller; they need less genes. 

71) A student complains that it makes no sense to worry about coliform bacteria in water, since we naturally have harmless coliforms in our intestines anyway. Is the student correct?

A) No. The coliforms in our intestines are usually harmful, causing intestinal infections. We need to constantly be on guard against this happening. Coliforms in water might add to this potential problem.

B) No. Not all coliforms are harmless to humans. It's best to keep coliforms OUT of our drinking water, since it's difficult to identify which ones might be harmless and which ones might be harmful.

C) No. Multiple types of coliforms in water might lead to greater antibiotic resistance in other aquatic bacteria, creating an environmental problem.

D) Yes. Regulatory agencies that monitor coliform levels in water simply need something to do to justify their existence. There is no real danger from coliforms in water supplies.

E) No. Clean water should not have any bacteria in it at all, so if any are present, they automatically pose a health risk to anyone swimming in or drinking that water.

72) Please select the definition that is INCORRECT.

A) Chemotrophs—organisms that obtain energy by oxidizing chemical compounds.

B) Chemolithotrophs—organisms that harvest energy by oxidizing inorganic chemicals.

C) Anoxygenic phototrophs—photosynthetic organisms that do not produce O2.

D) Nitrifiers—Gram-negative bacteria that obtain energy by oxidizing inorganic nitrogen compounds.

E) Mycobacteria—Gram-negative bacteria that group together to form complex fruiting bodies.

73) What roles do hydrogen gas and carbon dioxide play in the metabolism of methanogens?

A) Hydrogen gas is their energy source, and carbon dioxide is their terminal electron acceptor.

B) Hydrogen gas is their terminal electron acceptor, and carbon dioxide is their energy source.

C) Hydrogen gas is their energy source, and carbon dioxide is their carbohydrate source.

D) Hydrogen gas is their initial electron acceptor, and carbon dioxide is their energy source.

E) They use hydrogen gas in respiration, and they use carbon dioxide in photosynthesis.

74) Which of the following is NOT associated with a Clostridium species?

A) Tetanus

B) Botulism

C) Strep throat

D) Gas gangrene

E) Antibiotic-associated diarrheal disease

75) Which of the following are spirochetes?

A) Borrelia AND Treponema

B) Clostridium AND Borrelia

C) Leptospira AND Escherichia

D) Treponema AND Bacillus

E) Escherichia AND Neisseria

76) Which of the following genera have dormant forms that are resistant to extreme environmental conditions?

i. Bacillus

ii. Clostridium

iii. Neisseria

iv. Micrococcus

v. Leptospira

A) i, ii, AND v

B) i, iii, AND v

C) iii AND iv

D) i AND ii

E) ii ONLY

77) Which of the following genera are obligate intracellular parasites?

A) Chlamydia AND Mycoplasma

B) Chlamydia, Mycoplasma, AND Micrococcus

C) Escherichia AND Erlichia

D) Chlamydia, Coxiella, AND Rickettsia

E) Mycoplasma, Chlamydia, Coxiella, AND Rickettsia

78) Sulfolobus species are found at the surface of acidic sulfur-containing hot springs such as many of those found in Yellowstone National Park. They only grow at temperatures above 50°C and at a pH between 1 and 6. How would you classify these organisms?

A) Anaerobic, acidophilic mesophiles

B) Aerobic, acidophilic thermophiles

C) Microaerophilic, halotolerant basophiles

D) Aerobic, psychrophilic acidophiles

E) Psychrotrophic neutrophiles

79) Please select the FALSE statement regarding sheathed bacteria.

A) The sheath protects the bacteria from predators.

B) The sheath allows these bacteria to perform photosynthesis.

C) Sheathed bacteria frequently block industrial pipes.

D) Sheathed bacteria spread by means of swarmer cells.

E) The sheath allows these bacteria to attach to surfaces.

80) What distinguishes Staphylococcus, species from Streptococcus, Enterococcus and Lactococcus species?

A) Their morphology.

B) The nature of their cell walls.

C) The production of catalase.

D) Their ability to cause disease.

E) All of these.

You examine a patient who is complaining of belching (burping), bloating, and some vomiting. She also has some abdominal discomfort which she describes as a dull, burning pain that is worse when she is hungry and is often relieved when she takes antacids. You suspect that she may have Helicobacter pylori gastritis, and send her for a urea breath test. The breath test is positive; based on this, you get the patient's stool tested for blood, and you send her for an endoscopy, during which a biopsy is taken. Your diagnosis is confirmed by the results of these tests and that she does indeed have H. pylori.

81) Helicobacter pylori, a curved, Gram-negative microaerophilic motile bacterium. Based on this, how do you describe the organism to your patient?

A) The organism causing your signs and symptoms is a virus that requires oxygen for survival, has a thin cell wall composed of a compound called peptin, and can move by means of tail-like structures called flagella.

B) The organism causing your signs and symptoms is a bacterium that requires atmospheric levels of oxygen for survival, has a thick cell wall composed of a compound called peptidoglycan, and can move by means of appendages called cilia.

C) The organism causing your signs and symptoms is a protozoan that requires low levels of oxygen for survival, has a thin cell wall composed of a compound called chitin, and moves around your stomach by means of structures called flagella.

D) The organism causing your signs and symptoms is a bacterium that requires low levels of oxygen for survival, has a thin cell wall composed of a compound called peptidoglycan, and can move by means of tail-like structures called flagella.

E) The organism causing your signs and symptoms is a bacterium that cannot grow in the presence of oxygen, has a thick cell wall composed of a compound called peptidoglycan, and can move by means of tail-like structures called flagella.

82) Your patient asks you how a bacterium can survive in her stomach, which she knows is very acidic. You explain that

A) H. pylori produces urease that converts urea into carbon dioxide and ammonia; the ammonia neutralizes the pH of the stomach, allowing the bacteria to survive.

B) H. pylori has the ability to form endospores in hostile environmental conditions. It does this in the acidic stomach, only germinating once they reach the small intestine.

C) H. pylori is an acidophile, and as such prefers acidic pH levels of 1–3; gastric juices contain hydrochloric acid which has a very low pH.

D) H. pylori is encased in the very thick polysaccharide capsule that protects it from the degradative effects of the HCl found in the stomach.

E) H. pylori forms a biofilm with the other normal microbiota of the stomach. The structure of the biofilm covers and protects the bacteria within it.

83) Your patient asks you to explain how the urea breath test works. You tell her that in the test, she had been asked to swallow urea containing an unusual form of carbon—non-radioactive 13C (an isotope). After 10–30 minutes, she was asked to breathe into a receptacle, and her breath had been analyzed for the presence of this form of carbon in the carbon dioxide that she exhaled. You explain that the CO2 she exhaled contained 13C, so

A) her test indicates the presence of H. pylori—the organism produces ammoniase that breaks down the 13C-containing urea that the patient swallowed into urea and CO2 containing 13C which could be measured.

B) her test indicates the presence of H. pylori—the organism contains 13C in its cell wall, and in the presence of stomach acid, the cell wall is broken down to release CO2 containing 13C which could be measured.

C) her test indicates the presence of H. pylori—the organism produces urease that breaks down the 13C-containing urea that the patient swallowed into ammonia and CO2 containing 13C which could be measured.

D) her test indicates that her stomach cells used the 13C-containing urea in cellular respiration, producing glucose and releasing CO2 containing 13C as a byproduct.

E) nobody really understands how the urea breath test works, but that it is well known that anybody who drinks urea containing 13C and exhales CO2 containing this element afterwards needs treatment for an ulcer.

84) You prescribe two antibiotics for your patient, to be taken at the same time. You explain that two medications are used 

A) to prevent your patient from developing antibiotic resistance.

B) because H. pylori makes endospores and is very resistant.

C) because viruses are always treated with two different antibiotics.

D) because H. pylori forms cysts that are difficult to destroy.

E) to prevent the H. pylori from developing antibiotic resistance.

85) The blood in your patient's stool suggests an ulcer. The endoscopy confirms this. You discuss with the patient how H. pylori can cause ulcers. After H. pylori enters your body, it can cause damage to cells in the lining of the stomach, some of which usually produce a protective mucus layer. Once the bacteria have done enough damage, the mucus layer thins and stomach acid can get through the lining, leading to ulcers. You prescribe an antacid medication

A) to kill the H. pylori which can only live in acidic conditions.

B) to reduce the acidity of the stomach, thereby allowing the lining to heal.

C) to prevent the H. pylori from making CO2 which is causing the patient's burping.

D) to stimulate the patient's stomach E. coli population so it out-competes the pathogen.

E) All of the answer choices are correct.