Bacterial Cell Biology 2
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Questions and Answers

What is the primary source of ethanolamine in the gut?

  • Microbial cell membranes
  • Epithelial cells
  • Inflamed gut tissue
  • Plant and animal cell membranes (correct)

    • Which of the following bacteria utilizes EUT for growth?

  • Clostridium difficile
  • Salmonella enterica
  • Fusobacterium nucleatum
  • All of the above (correct)

    • What is the term for the time required for a population of microbial cells to double?

  • Lag phase
  • Stationary phase
  • Generation time (correct)
  • Exponential growth

    • What is the process of cell division in which new cell material is produced from a single point?

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

    In which phase of microbial growth does cell growth slow down due to nutrient depletion or waste buildup?

    <p>Stationary phase</p> Signup and view all the answers

    What is the term for the process of microbial cells remaining alive for months despite being in a dormant state?

    <p>Death phase</p> Signup and view all the answers

    What is the primary function of the slime layer and capsule on the bacterial cell surface?

    <p>To aid in attachment to solid surfaces and prevent dehydration</p> Signup and view all the answers

    What is the primary function of fimbriae in bacterial cells?

    <p>To enable cells to stick to surfaces including animal tissues</p> Signup and view all the answers

    What is the primary function of pili in gram-negative bacteria?

    <p>To enable genetic exchange through horizontal gene transfer</p> Signup and view all the answers

    What is the primary function of the lipopolysaccharide layer in gram-negative bacteria?

    <p>To simulate CD14 and trigger immune response</p> Signup and view all the answers

    What is the primary function of gram-negative secretion systems?

    <p>To enable the secretion of molecules from the cell interior to its exterior</p> Signup and view all the answers

    What is the primary function of commensal bacteria in the context of inflammatory endocytosis?

    <p>To prevent inflammatory endocytosis</p> Signup and view all the answers

    What is the primary function of dipicolinic acid in endospores?

    <p>It dehydrates the spores and protects DNA from denaturing</p> Signup and view all the answers

    What triggers the formation of endospores in Bacillus?

    <p>Lack of nutrients such as carbon or nitrogen</p> Signup and view all the answers

    What is the role of small acid-soluble spore proteins (SASPs) in endospores?

    <p>They bind to DNA</p> Signup and view all the answers

    What is the minimum temperature that some endospores can withstand?

    <p>150 degrees C</p> Signup and view all the answers

    What is the result of outgrowth in the life cycle of an endospore-forming bacteria?

    <p>Emergence of a vegetative cell</p> Signup and view all the answers

    What is the primary mode of dispersal of endospores?

    <p>Through wind, water, and animal gut (faeces)</p> Signup and view all the answers

    What is the primary mechanism by which cyanobacteria move?

    <p>Polysaccharide slime secretion</p> Signup and view all the answers

    How do bacterial cells respond to chemical gradients?

    <p>By changing their movement patterns</p> Signup and view all the answers

    What is the purpose of tumbles in bacterial movement?

    <p>To change direction randomly</p> Signup and view all the answers

    How do phototrophic bacteria optimize photosynthesis?

    <p>By positioning themselves in optimal light conditions</p> Signup and view all the answers

    How do bacterial cells sense chemical gradients?

    <p>By sampling the concentration and comparing to previous values</p> Signup and view all the answers

    What is the role of the signalling and gene regulatory network in chemotaxis?

    <p>To implement the 'memory' of previous concentrations</p> Signup and view all the answers

    What is the primary component of the flagellum motor that anchors it to the cytoplasmic membrane and cell wall?

    <p>Central rod</p> Signup and view all the answers

    What is the direction of growth for the flagella filament in Escherichia and Salmonella?

    <p>From the tip to the base</p> Signup and view all the answers

    What is the mechanism by which proton translocation through Mot proteins exerts force on the rotor proteins?

    <p>Electrostatic forces on helically arranged charges</p> Signup and view all the answers

    What is the term for the type of flagellation in which flagella are located in many places around the surface of the cell?

    <p>Peritrichous flagellation</p> Signup and view all the answers

    How many genes are involved in flagella biosynthesis in Escherichia and Salmonella?

    <p>Upwards of 50 genes</p> Signup and view all the answers

    What is the function of the Mot proteins in the flagellum motor?

    <p>They surround the inner rings and form the stator</p> Signup and view all the answers

    What is the primary reason why endospores are highly heat-resistant?

    <p>Because of the unique substance dipicolinic acid that confers heat resistance</p> Signup and view all the answers

    What is the event that triggers the activation of spores in Bacillus?

    <p>When spores are heated for several minutes</p> Signup and view all the answers

    What is the primary role of small acid-soluble spore proteins (SASPs) in endospores?

    <p>To bind to DNA and protect it from denaturation</p> Signup and view all the answers

    What is the final stage of the life cycle of an endospore-forming bacteria?

    <p>Vegetative cell growth</p> Signup and view all the answers

    What is the primary mode of dispersal of endospores?

    <p>Easily dispersed by wind, water, or animal gut (faeces)</p> Signup and view all the answers

    What is the minimum temperature that some endospores can withstand?

    <p>150°C</p> Signup and view all the answers

    What is the event that occurs after the spore is activated and exposed to certain nutrients?

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

    What is the term for the survival structure produced by certain gram-positive bacteria?

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

    What is the term for the type of flagellation in which flagella are located at one pole of the cell?

    <p>Polar flagellation</p> Signup and view all the answers

    What is the primary component of the flagellum motor that anchors it to the cytoplasmic membrane and cell wall?

    <p>Basal body</p> Signup and view all the answers

    In which bacteria is the flagella filament known to grow from the tip?

    <p>E. coli and Salmonella</p> Signup and view all the answers

    What is the primary function of the Mot proteins in the flagellum motor?

    <p>To surround the inner rings</p> Signup and view all the answers

    What is the term for the helically arranged charges on the rotor proteins?

    <p>Helical charges</p> Signup and view all the answers

    What is the primary function of the L ring and P ring in the flagellum motor?

    <p>To anchor the motor to the outer membrane and peptidoglycan layer</p> Signup and view all the answers

    What is the primary function of the flagellum?

    <p>Swimming motility</p> Signup and view all the answers

    What is the number of genes involved in flagella biosynthesis in Escherichia and Salmonella?

    <p>Upwards of 50</p> Signup and view all the answers

    Which type of taxis involves movement towards or away from ionic strength?

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

    What is the primary function of the sensor kinase protein in a two-component system?

    <p>To phosphorylate itself in response to an external signal</p> Signup and view all the answers

    What is the purpose of quorum sensing in Vibrio cholerae?

    <p>To monitor the population level and secrete virulence factors at low population density</p> Signup and view all the answers

    What is the role of the response regulator protein in a two-component system?

    <p>To bind to DNA</p> Signup and view all the answers

    What is the purpose of the two-component system in bacterial cells?

    <p>To regulate gene expression based on environmental fluctuations</p> Signup and view all the answers

    What is the primary mechanism by which bacteria respond to changes in chemical gradients?

    <p>Sensing temporal differences in concentration</p> Signup and view all the answers

    What is the function of autoinducers AI-2 and CAI-1 in quorum sensing?

    <p>To increase the secretion of virulence factors</p> Signup and view all the answers

    What is the role of the signalling and gene regulatory network in chemotaxis?

    <p>To implement the 'memory' of the bacterial cell</p> Signup and view all the answers

    What is the primary function of chemotaxis in bacterial cells?

    <p>To respond to chemical gradients</p> Signup and view all the answers

    What is the role of the sensor kinase protein in a two-component system?

    <p>To receive signals from the environment and phosphorylate itself</p> Signup and view all the answers

    What is the purpose of the 'tumbles' in bacterial movement?

    <p>To change direction randomly</p> Signup and view all the answers

    How do phototrophic bacteria optimize photosynthesis?

    <p>By positioning themselves in optimal light conditions</p> Signup and view all the answers

    What is the mechanism by which bacterial cells move towards a chemical attractant?

    <p>By increasing the length of runs</p> Signup and view all the answers

    What is the term for the directed movement of an organism in response to a chemical gradient?

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

    How do bacterial cells respond to the presence of a chemical attractant?

    <p>By increasing the length of runs</p> Signup and view all the answers

    What is the purpose of the polysaccharide slime secreted by cyanobacteria?

    <p>To facilitate gliding motility</p> Signup and view all the answers

    What is the term used to describe the growth of microbial cells attached to a surface?

    <p>Biofilm formation</p> Signup and view all the answers

    Which of the following regions of the GI tract has the highest concentration of microbial cells per gram of tissue?

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

    What is the primary function of butyrate produced by microorganisms in the colon?

    <p>Energy source for colonic epithelial cells</p> Signup and view all the answers

    What term describes an imbalance in the composition of the microbiota, leading to disease?

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

    What is the primary role of the gut microbiome in human health?

    <p>Essential to human health</p> Signup and view all the answers

    What is the term used to describe the complex carbohydrates that are digested by the gut microbiome?

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

    What is the approximate pH of the stomach?

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

    What is the term used to describe the attached polysaccharide matrix with embedded bacterial cells?

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

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