Deck 24: Microbial Symbioses with Humans

Question 1

Clostridium difficile infections most often occur

A) following antibiotic treatment.
B) following a fecal transplant.
C) following a dietary change.
D) following the use of a new probiotic.

Answer 1

A

Question 2

What is TRUE about stomach microbiota?

A) Few microbes can survive because it is so acidic.
B) The alkaline environment supports a wide variety of species.
C) Despite the acidic of the stomach, diverse phylotypes of resident microbes thrive in the stomach.
D) There is a rich diversity of transient microbes, but few resident microbes.

Answer 2

C

Question 3

Individuals who have chronic periodontitis tend to have

A) lower microbial diversity than those without.
B) significantly greater microbial diversity than those without.
C) slightly greater microbial diversity than those without.
D) unpredictable levels of microbial diversity in comparison to those without chronic periodontitis.

Answer 3

A

Question 4

Which of the following are NOT found in the gastrointestinal tract of healthy humans?

A) Bacteroides
B) Clostridium
C) Escherichia coli
D) protists

Question 5

Only particles smaller than ________ μm in diameter reach the lungs.

A) 10
B) 20
C) 30
D) 40

Question 6

Normal microbiota in the duodenum is

A) similar to the microbiota in the stomach.
B) dominated by aerobic organisms.
C) tolerant to highly alkaline environments.
D) tolerant to high salinity.

Question 7

The vagina of an adult female is

A) highly acidic.
B) highly alkaline.
C) weakly acidic.
D) weakly alkaline.

Question 8

Which of the following is NOT true about breast fed infants compared with those fed formula?

A) They have greater numbers of Bifidobacterium longum.
B) They have greater numbers of Clostridium difficile.
C) They have greater numbers of Citrobacter spp.
D) They have greater numbers of Enterobacter cloacae.

Question 9

The damaged areas of teeth caused by organic acids produced by dental plaque are called

A) degenerative plaque.
B) calcified plaque.
C) periodontal disease.
D) dental caries.

Question 10

Vaginitis commonly results from overgrowth of

A) Candida.
B) Trichomonas vaginalis.
C) Candida and Trichomonas vaginalis.
D) Neither Candida nor Trichomonas vaginalis.

Question 11

Following antibiotic therapy, patients are often administered ________ to facilitate recolonizaton of normal microbiota in the intestines.

A) fluoride
B) iron
C) probiotics
D) antivirals

Question 12

The following compounds are all produced by intestinal microbiota EXCEPT

A) thymine.
B) vitamin C.
C) vitamin B₁₂.
D) vitamin K.

Question 13

A microbial community that does not change when exposed to stressors is called

A) resilient.
B) resistant.
C) robust.
D) regimented.

Question 14

What is the difference between vaginitis and vaginosis?

A) Vaginitis is more serious and vaginosis is subclinical.
B) Vaginosis is more serious and vaginitis is subclinical.
C) Vaginosis occurs first and then develops into vaginitis.
D) Vaginosis is an acute infection and vaginitis is always a chronic infection.

Question 15

Common probiotics include

A) Bifidobacterium species.
B) Clostridium species.
C) Escherichia coli.
D) Corynebacterium species.

Question 16

The pouch at the beginning of the large intestine is called the

A) cardia.
B) ileum.
C) colon.
D) cecum.

Question 17

Children with severe dental caries tend to have elevated levels of all of the following bacteria EXCEPT

A) Aestuariimicrobium.
B) Streptococcus.
C) Granulicatella.
D) Actinomyces.

Question 18

Which of these microorganisms is most likely to be found in the human stomach?

A) Helicobacter pylori
B) Streptococcus sobrinus
C) Streptococcus mutans
D) Roseobacter denitrificans

Question 19

One microenvironment of the skin is an area where glands produce an oily substance called

A) mucus.
B) sebum.
C) fimbrae.
D) lipid A.

Question 20

What is the role of fecal transplants in medicine?

A) They can provide a healthy microbiota to help treat Clostridium difficle infections.
B) They act as prebiotics to encourage healthy microbial growth.
C) They remove the unhealthy microbes, allow the individual an opportunity to have recolonization by non-pathogens ingested with food.
D) They can be used to treat infections caused by the overgrowth of Lactobacilli.

Question 21

Based upon microbiome projects, the dominant microbial species on the skin is

A) Corynebacterium species.
B) Streptococcus species.
C) Staphylococcus species.
D) Propionibacterium species.

Question 22

Which study set out to generate genomic sequences from 200 strains of bacteria isolated from the human body?

A) the Human Microbiome Project
B) NIH JumpStart Program
C) MetaGenoPolis
D) the Integrative Human Microbiome Project

Question 23

Which of the following is the genus represented by the greatest diversity of phylotypes on the skin?

A) Bacteriodes
B) Firmicutes
C) Actinobacteria
D) Proteobacteria

Question 24

The human gastrointestinal tract includes all of the following EXCEPT the

A) small intestine.
B) stomach.
C) large intestine.
D) epiglottis.

Question 25

Which of the following is TRUE about research on the human microbiome?

A) Advanced nucleic acid sequencing techniques were needed before a good understanding of its microbial abundance and diversity could be developed.
B) Culture-dependent techniques fully elucidated its microbial diversity.
C) Cultivation was unimportant in studying its microbial diversity.
D) None of the answers are correct.

Question 26

Important bacterial populations in the stomach include

A) Firmicutes.
B) Bacteriodetes.
C) Veilonella.
D) All of these answer choices.

Question 27

Normal microbiota helps to ________ colonization of pathogenic organisms.

A) promote
B) prevent
C) maintain
D) accelerate

Question 28

Extensive microbial growth in a thick bacterial layer on the teeth is called

A) dental plaque.
B) dental caries.
C) dental biofilm.
D) periodontitis.

Question 29

More frequent cases of severe C. difficile infection since 2003 is attributed to

A) the emergence of more virulent and toxigenic strains.
B) the increased use of probiotics.
C) problems with hospital hygiene and increased transmission.
D) dietary changes in the human population.

Question 30

________ dominate the infant gut microbiota.

A) Candida
B) Actinobacteria
C) Firmicutes
D) Corynebacteria

Question 31

The host-microbiome supraorganism refers to

A) the human body and all of the microbes found within it, but not those on the external surfaces.
B) a nonhuman animal and all of the microbes found within it, but not those on the external surfaces.
C) a human body and all of its commensal microbes.
D) a body and all of its associated microbes.

Question 32

Which of the following is known to be TRUE about dog owners and their dogs?

A) Dog owners have fewer skin microbes than those who don't own dogs.
B) Dog owners have more skin microbes than those who don't own dogs.
C) Skin microbes are more common between dog owners and their own dogs than between dog owners and other dogs.
D) Skin microbes are similar between dog owners and dogs in general, with no difference in similarity when dogs and their owners are compared with other human-dog pairs.

Question 33

Which of the following is a benefit of studying the human microbiome?

A) It may allow for the development of personalized medical treatments.
B) It may allow for more finely targeted probiotics.
C) It may allow for increased recognition of disease biomarkers.
D) All of these answer choices are possible benefits.

Question 34

Which of the following is TRUE of vaginal bacterial communities?

A) Those dominated by Lactobacillus crispatus are more resilient than those dominated by Lactobacillus iners.
B) Those dominated by Lactobacillus crispatus are less resilient than those dominated by Lactobacillus iners.
C) Lactobacillus iners is always associated with vaginosis, but Lactobacillus crispatus is not.
D) Lactobacillus crispatus is always associated with vaginosis, but Lactobacillus iners is not.

Question 35

The gut microbiota resembles the adult microbiota

A) by 12 months of age.
B) by 1 month of age.
C) around age 15.
D) around age 3.

Question 36

Which of the following is TRUE about the comparison between the mouse gut and the human gut?

A) The stomach is relatively larger in mice.
B) The colon and cecum are relatively larger in mice.
C) The small intestine is relatively larger in mice.
D) The esophagus and stomach are relatively larger in mice.

Question 37

Which of the following environmental and host factors influence the composition of the resident microbiota on the skin?

A) age
B) personal hygiene
C) weather
D) age, personal hygiene, and weather

Question 38

Which of the following is TRUE regarding the interaction between hormones and vaginal microbial diversity?

A) There is a direct relationship between estradiol levels and microbial diversity.
B) There is an inverse relationship between estradiol levels and microbial diversity.
C) There is a direct relationship between luteinizing hormone levels and microbial diversity.
D) There is an inverse relationship between luteinizing hormone levels and microbial diversity.

Question 39

The collective term for the functional collection of microbes living on or in the human body, as opposed to a general term for organisms in an environmental habitat, is

A) the human microbiome.
B) the microbiota.
C) transient microbial flora.
D) pathogens.

Question 40

Infants born via C-section have

A) fewer Bacteriodes species than those born vaginally.
B) approximately 72% of the species present matching those of their mothers.
C) relatively less Staphylococcus aureus than those born vaginally.
D) fewer Haemophilus influenzae than those born vaginally.

Question 41

Probiotics do not contain living microbes.

Question 42

Which of the following is NOT true of human gut microbes?

A) The population size is low, but the diversity is high.
B) They produce and excrete amino acids.
C) They help catabolize polysaccharides.
D) They are involved in the "maturing" of the digestive tract.

Question 43

The use of fecal transplants has dramatically improved outcomes for patients with Clostridium difficile infections.

Question 44

Bacteria found in the mouth in the first years of life are well-adapted to biofilm formation.

Question 45

Protists are NOT normally found in the gastrointestinal tract of healthy individuals.

Question 46

A vaginal swab would suggest vaginosis if there were relatively high numbers of gram-positive rods and relatively low numbers of gram variable rods.

Question 47

The human oral microbiota consists of

A) a small group of phylogenetically related aerobic microorganisms.
B) diverse aerobic and anaerobic microorganisms.
C) monoculture biofilms on tooth surfaces.
D) the same phyla that are found in the human gut.

Question 48

Gut microbiota is known to be linked with

A) obesity and inflammatory bowel syndrome.
B) obesity, but not with inflammatory bowel syndrome.
C) inflammatory bowel syndrome, but not with obesity.
D) inflammatory bowel syndrome and Crohn's disease only, but not with ulcerative colitis.

Question 49

Clostridium difficile commonly develops in hospitalized patients, but is increasingly seen in non-hospitalized patients traditionally considered to be at lower risk.

Question 50

What happens when mice grown in the absence of microbes are inoculated with healthy cecal material from other mice?

A) Genes associated with glucose uptake, lipid absorption, and lipid transport are activated and the mice gain body fat without increasing energy intake.
B) Genes associated with glucose uptake, lipid absorption, and lipid transport are activated and the mice gain body fat as a result of taking in more food.
C) Genes associated with protein uptake, lipid break down, and lipid transport are activated and the mice lose body fat without changing their food intake.
D) Genes associated with protein uptake, lipid break down, and lipid transport are deactivated and the mice lose body fat as a result of taking in less food.

Question 51

The Nugent score is used to diagnose

A) urinary tract infections.
B) ulcerative colitis.
C) vaginosis.
D) inflammatory colitis.

Question 52

Weight gain and obesity may be partly caused by certain gut microbial communities that

A) absorb more vitamins and essential amino acids.
B) produce more volatile fatty acids by fermentation.
C) stimulate the gut endothelium to absorb more sugars.
D) produce more hydrogen gas by fermentation.

Question 53

Normal microbiota is usually found in the blood, lymph, and nervous systems of the body.

Question 54

The most heavily colonized human organ by bacteria is the ________, containing 10¹¹‐10¹² bacterial cells per gram.

A) mouth
B) small intestine
C) large intestine
D) skin

Question 55

Which of the following is NOT a function of the human gut microbiome?

A) production of essential amino acids and vitamins
B) production of volatile fatty acids from polysaccharides
C) iron and trace metal absorption
D) maturation of the gastrointestinal tract

Question 56

All microorganisms that live in the human body are harmful.

Question 57

Bacteria make up about one-third the weight of fecal matter.

Question 58

The human microbiome contains all

A) organisms present on the skin.
B) organisms within the digestive system.
C) organisms present in and on the body.
D) organisms present on the skin or in the digestive system only.

Question 59

Which of the following is NOT a major question in the Human Microbiome Project?

A) Are differences in the relative abundance of different bacteria important?
B) Do differences in the human microbiome correlate with differences in human health?
C) Is there a correlation between microbial population structure and host genotype?
D) How can we reduce the number of microbes on the human body?

Question 60

The presence of Propionibacterium acnes is always associated with inflammatory disease.

Question 61

Some yogurts contain probiotics and prebiotics.

Question 62

Ammonia-oxidizing Archaea can be found on the skin.

Question 63

Explain how diet plays a role in host susceptibility to infection, focusing on the role of diet in the development of inflammatory bowel disease.

Question 64

A healthy vaginal microbiome is dominated by Candida.

Question 65

Elderly individuals have greater proportions of Bacteroidetes in their gut microbiota compared with younger individuals.

Question 66

The male reproductive tract is generally sterile except for the distal portion of the urethra.

Question 67

The upper respiratory tract usually has a considerable amount of resident microflora in a healthy adult.

Question 68

Volatile fatty acids include acetate, proprionate, and butyrate.

Question 69

Methanogenic Archaea are more common in obese humans compared with thin humans.

Question 70

Biofilms in the human mouth primarily contain pathogens.

Question 71

Goblet cells in the intestine produce antimicrobial peptides.

Question 72

The gut microbiota is relatively stable over long time periods in healthy adults, suggesting its highly evolved role in the human body.

Question 73

Crohn's disease and ulcerative colitis are examples of inflammatory bowel syndromes.

Question 74

Malassezia spp. are the most common fungi present on the skin of humans.

Question 75

Why are some microorganisms specialized to only certain parts of the body? Describe an example that supports your answer.

Question 76

Consumers can purchase probiotic foods that are 100% proven to be highly effective.

Question 77

Goblet cells in the intestine secrete mucin.

Question 78

Vaginal acidity in the adult female is due to acid production by Lactobacillus acidophilus.

Question 79

A plant-rich diet increases the risk of inflammatory bowel disease, a leaky gut, and inflammation.

Question 80

Volatile fatty acids are produced primarily from the breakdown of proteins.