BIOL212 W5-1
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What is the primary function of the human gastrointestinal tract?

  • Production of hormones
  • Digestion of food and absorption of nutrients (correct)
  • Storage of waste products
  • Detoxification of harmful substances

    • Which microbial population is most commonly found in the gastric fluid?

  • Firmicutes (correct)
  • Bacteroidetes
  • Proteobacteria
  • Actinobacteria

    • Which factor primarily influences the microbial populations in the GI tract?

  • Genetics of the host
  • Age of the individual
  • Environmental temperature
  • Physical conditions and diet (correct)

    • What is the pH level of the stomach and duodenum, which prevents many organisms from colonizing?

    <p>pH 2</p> Signup and view all the answers

    Where is Helicobacter pylori predominantly found when present in the human body?

    <p>Gastric mucosa</p> Signup and view all the answers

    Which of the following describes the role of the large intestine in relation to microbial activity?

    <p>In vivo fermentation vessel</p> Signup and view all the answers

    What percentage of the world's population is estimated to carry Helicobacter pylori?

    <p>50 percent</p> Signup and view all the answers

    Which of the following microbial groups is primarily associated with the mucus layer of the stomach?

    <p>Firmicutes</p> Signup and view all the answers

    What is the approximate surface area of the human gastrointestinal tract?

    <p>400 m²</p> Signup and view all the answers

    Which of the following best describes the metabolic function of intestinal microorganisms?

    <p>Carry out essential metabolic reactions</p> Signup and view all the answers

    What is a microbiome primarily defined as?

    <p>A functional collection of microbes in an environmental system</p> Signup and view all the answers

    Which body site is NOT mentioned as part of the human microbiome?

    <p>Lungs</p> Signup and view all the answers

    What is one potential future benefit of understanding the human microbiome?

    <p>Development of biomarkers for disease predisposition</p> Signup and view all the answers

    Which statement best describes the gastrointestinal microbiota in humans?

    <p>Human beings are monogastric and omnivorous.</p> Signup and view all the answers

    What is a primary method for identifying different microbiota in the human body?

    <p>Advanced sequencing techniques</p> Signup and view all the answers

    What is a common misconception about the human microbiome?

    <p>Microbiomes are static and do not change over time.</p> Signup and view all the answers

    At what stage does gut colonization begin in humans?

    <p>At birth</p> Signup and view all the answers

    Which of the following questions is relevant to current studies on the human microbiome?

    <p>Do microbiota differences correlate with human health?</p> Signup and view all the answers

    What is true about the relationship between the human host and microbiota?

    <p>There are complex interactions between the host and its microbiota.</p> Signup and view all the answers

    What is one characteristic of the normal human microbiota?

    <p>It varies greatly depending on the microhabitat.</p> Signup and view all the answers

    Which bacterial phylum is primarily associated with the production of vitamin B12 in the human gut?

    <p>Firmicutes</p> Signup and view all the answers

    What is the significance of the stable gut microbiota in individuals?

    <p>It may regulate metabolism and influence obesity risk.</p> Signup and view all the answers

    Which of the following bacteria is primarily responsible for the formation of dental plaque?

    <p>Streptococcus</p> Signup and view all the answers

    Which of the following enterotypes is enriched in Firmicutes?

    <p>Ruminococcus</p> Signup and view all the answers

    What role do fermenting bacteria play in dental health?

    <p>They produce acid that can erode tooth enamel.</p> Signup and view all the answers

    Which of the following microbial groups is noted for colonizing below the gum line?

    <p>Fusobacterium</p> Signup and view all the answers

    What role does saliva play in the oral cavity's microbial environment?

    <p>Contains antimicrobial enzymes that inhibit microbial growth.</p> Signup and view all the answers

    What essential role does intrinsic factor play in the context of vitamin B12?

    <p>It is necessary for the absorption of vitamin B12.</p> Signup and view all the answers

    Which condition is believed to be related to periodontal disease?

    <p>Cardiovascular disease</p> Signup and view all the answers

    Which major group of bacteria predominantly makes up the human gut microbiota?

    <p>Firmicutes</p> Signup and view all the answers

    In healthy adults, which part of the respiratory tract is devoid of normal microbiota?

    <p>Lower respiratory tract</p> Signup and view all the answers

    How do microbial metabolites from the gut impact host physiology?

    <p>They can modify hormones and influence metabolic functions.</p> Signup and view all the answers

    What is the primary mechanism by which microbes are cleared from the upper respiratory tract?

    <p>Mucus trapping and ciliary movement</p> Signup and view all the answers

    Which genus of bacteria is the most abundant in the oral cavity?

    <p>Firmicutes</p> Signup and view all the answers

    Which enterotype is characterized by a higher abundance of Prevotella?

    <p>Enterotype 2</p> Signup and view all the answers

    What unique property do the three identified gut enterotypes possess?

    <p>They are functionally and phylogenetically distinct.</p> Signup and view all the answers

    Which of the following can contribute to a breakdown in the mutualism of healthy microbial flora?

    <p>Formation of dental plaque</p> Signup and view all the answers

    Which of the following is NOT a characteristic of aerobe microbes in the oral cavity?

    <p>They predominantly colonize the gum line.</p> Signup and view all the answers

    What is one of the primary consequences of vitamin B12 deficiency?

    <p>Anemia.</p> Signup and view all the answers

    What is the main composition of dental plaque?

    <p>A complex mixed-culture biofilm</p> Signup and view all the answers

    Which statement about the differences between mice and humans in microbial studies is correct?

    <p>Mice have a cecum larger than that of humans, allowing for more fermentation.</p> Signup and view all the answers

    What is a significant factor that influences the nature of an infant's gut microbiome at birth?

    <p>Whether the infant is born vaginally or via Cesarean section.</p> Signup and view all the answers

    Which statement best describes the role of early colonizing microbes for an infant?

    <p>They contribute to the production of short-chain fatty acids.</p> Signup and view all the answers

    What aspect of aging affects the microbial diversity in the gut?

    <p>A decline in overall microbial diversity.</p> Signup and view all the answers

    How does the feeding method affect the gut microbiome of infants?

    <p>Breast milk contains oligosaccharides that support the growth of beneficial bacteria.</p> Signup and view all the answers

    What does the Integrative Human Microbiome Project (iHMP) primarily focus on?

    <p>Studying the microbiome in relation to three specific health conditions.</p> Signup and view all the answers

    Which statement highlights a limitation of using mouse models in microbiome research?

    <p>Significant differences exist between mouse and human gut fermentation processes.</p> Signup and view all the answers

    What is the role of antibiotic therapy in mouse models used for microbiome research?

    <p>It creates a baseline for studying microbiome recovery.</p> Signup and view all the answers

    What key feature of the gut microbiome undergoes significant changes during early life?

    <p>The microbial population transitions towards a stable adult profile.</p> Signup and view all the answers

    Which microbial organism is primarily responsible for maintaining an acidic environment in the female vagina?

    <p>Lactobacillus acidophilus</p> Signup and view all the answers

    What is the predominant reason for the higher prevalence of urinary tract infections in women compared to men?

    <p>Shorter urethras in women</p> Signup and view all the answers

    Which factor does NOT influence the composition of skin microbiota?

    <p>Sex</p> Signup and view all the answers

    Which of the following is a common cause of hospital-acquired urinary tract infections?

    <p>Presence of catheters</p> Signup and view all the answers

    In the context of skin microbiota, which microenvironment is characterized by a higher moisture content?

    <p>Moist skin</p> Signup and view all the answers

    Which of the following is NOT a phase of the Human Microbiome Project?

    <p>Phase 4 - HMP4</p> Signup and view all the answers

    What is a significant environmental factor influencing the composition of skin microbiota?

    <p>Personal hygiene</p> Signup and view all the answers

    Which organisms can cause urinary tract infections in immunocompromised patients?

    <p>Any organism capable of surviving in the urinary tract</p> Signup and view all the answers

    What is the primary method used by Lactobacillus acidophilus to produce lactic acid?

    <p>Fermentation of glycogen</p> Signup and view all the answers

    What is the total approximate number of microorganisms residing on the skin of an average adult?

    <p>10 billion</p> Signup and view all the answers

    What is the primary purpose of SER-109 in the context of microbiome therapeutics?

    <p>To prevent recurrence of C.difficile</p> Signup and view all the answers

    Which of the following statements about the safety profile of SER-109 is accurate?

    <p>It has a favorable safety profile based on clinical trials.</p> Signup and view all the answers

    What is the significance of the FDA granting Breakthrough Therapy designation to SER-109?

    <p>It allows for expedited development and review due to unmet medical needs.</p> Signup and view all the answers

    How are the bacterial spores in SER-109 prepared for therapeutic use?

    <p>By fractionating targeted bacteria and inactivating potential pathogens.</p> Signup and view all the answers

    In the method of stool collection for fecal transplants, what process is used on the collected stool?

    <p>It is diluted and filtered using sterile saline.</p> Signup and view all the answers

    What is a consequence of early oral antibiotic use in infants?

    <p>It increases the likelihood of microbial imbalance or dysbiosis.</p> Signup and view all the answers

    Which bacterial group is more prevalent in genetically obese mice compared to their normal counterparts?

    <p>Firmicutes</p> Signup and view all the answers

    What is a shared characteristic of Clostridium difficile related to antibiotic use?

    <p>It forms spores which contribute to its antibiotic resistance.</p> Signup and view all the answers

    Which component is a major product of intestinal microbiota fermentation of dietary fibers?

    <p>Volatile fatty acids (VFAs)</p> Signup and view all the answers

    What factors could complicate the transferability of gut microbiota?

    <p>Age and health of the donor</p> Signup and view all the answers

    Which of the following statements about Inflammatory Bowel Disease (IBD) is accurate?

    <p>IBD may be transmissible within families.</p> Signup and view all the answers

    What is the primary reason that fecal transplants are used therapeutically?

    <p>They restore microbial diversity lost to antibiotics.</p> Signup and view all the answers

    What impact does toxin B from Clostridium difficile have on the intestinal wall?

    <p>It increases intestinal permeability.</p> Signup and view all the answers

    Which characteristic allows Clostridium difficile to resist decontamination efforts in hospital environments?

    <p>Spore formation.</p> Signup and view all the answers

    What is the relationship between antibiotic use and Clostridium difficile infections?

    <p>Antibiotics allow Clostridium difficile to outgrow normal intestinal flora.</p> Signup and view all the answers

    What is one of the exclusion criteria for donors in fecal microbiota transplantation (FMT)?

    <p>Frequent travels.</p> Signup and view all the answers

    Which type of colitis is characterized by severe inflammation and can result from Clostridium difficile infection?

    <p>Pseudomembranous colitis.</p> Signup and view all the answers

    What is a potential avenue of research regarding the application of fecal microbiota transplantation (FMT)?

    <p>Management of obesity and irritable bowel syndrome.</p> Signup and view all the answers

    What kind of toxins does Clostridium difficile produce and what are their primary functions?

    <p>An enterotoxin that stimulates cytokine release and a cytotoxin that affects intestinal permeability.</p> Signup and view all the answers

    What is a common gastrointestinal disease associated with antibiotic use?

    <p>Clostridium difficile infection.</p> Signup and view all the answers

    What primary mechanism does Clostridium difficile's spore formation utilize to enhance its survival?

    <p>Facilitating resistance to environmental stressors.</p> Signup and view all the answers

    In the context of C. difficile infections, what is a consequence of neutrophil cytokine release in the intestinal environment?

    <p>Promotion of inflammation leading to diarrhea.</p> Signup and view all the answers

    Study Notes

    Microbial Symbioses with Humans

    • All sites on a human containing microorganisms are part of a microbiome.
    • A microbiome is a functional collection of varying microbes in a specific environment, for example the human microbiome.
    • Microbiota describes all microbes in a specific habitat, such as skin microbiota.
    • Microhabitats support different microbes, so, for example, the skin has different microbes than the mouth.

    Structure and Function of the Healthy Adult Human Microbiome

    • There are approximately 1013 microbes in the human microbiome (Figure 24.1). They live in complex communities.
    • Topics covered include an overview of the human microbiome, gastrointestinal microbiota, oral cavity and airways, urogenital tracts and their microbes, and the skin and its microbes (24.1, 24.2, 24.3, 24.4, 24.5).

    Benefit and complexity of Human Microbiome

    • Future benefits of knowing the human microbiome include the development of biomarkers to predict disease predisposition, design of targeted therapies, and personalized drug therapies and probiotics.
    • Complex interactions exist between the host and its microbiota.

    Experimental Protocols and Body Target Sites

    • Most bacteria cannot be cultured, but advanced sequencing techniques identify different microbiota at various body sites (Figure 24.2).
    • Studies are done to understand the nature of normal microbiota (Table 24.1).

    Overview of Major Microbial Populations

    • Figure 24.2 displays a breakdown of major microbial populations in different body sites (e.g., skin, saliva, urogenital tract, gastrointestinal tract).

    Basic questions about the human microbiome

    • Do individuals share a core human microbiome?
    • Is there a correlation between the composition of microbiota colonizing a body site and host genotype?
    • Do differences in the human microbiome correlate with differences in human health?
    • Are differences in the relative abundance of specific bacterial populations important to either health or disease?

    Gastrointestinal Microbiota

    • Humans are monogastric and omnivorous.
    • Gut microbes impact early development, health, and disease predisposition.
    • Gut colonization begins at birth.
    • The human GI tract consists of the stomach, small intestine, and large intestine (Figure 24.3), totaling 400 m² of surface area.
    • The GI tract is responsible for digesting food, absorbing nutrients, and containing 1013 to 1014 microbial cells.
    • Indigenous microbial flora produces nutrients.

    The Stomach and Small Intestine

    • Microbial populations in different GI tract areas are influenced by diet and local conditions.
    • Stomach and duodenum (~pH 2) prevent many organisms from colonizing, but a rich microbiome exists in a healthy stomach.
    • Firmicutes, Bacteroidetes, and Actinobacteria commonly exist in the gastric fluid, while Firmicutes and Proteobacteria are more common in the stomach's mucus layer.
    • Helicobacter pylori, discovered in the 1980s, is found in approximately 50% of the global population, residing in the gastric mucosa.

    The Large Intestine

    • The colon acts as an in vivo fermentation system using ingested food nutrients.
    • Most organisms are restricted to the colon's lumen; others reside in mucosal layers (Figure 24.6).

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    Description

    Explore the diversity and function of the human microbiome. This quiz covers microbial symbioses, the structure and function of the healthy adult microbiome, and its implications for health and disease. Understand the significance of various microbiota found in different human microhabitats.

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