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 (B)</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 (D)</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 (D)</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 (D)</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 (A)</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 (C)</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 (D)</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 (D)</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 (B)</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 (D)</p> Signup and view all the answers

What triggers the formation of endospores in Bacillus?

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

What is the minimum temperature that some endospores can withstand?

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

What is the primary mode of dispersal of endospores?

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

What is the primary mechanism by which cyanobacteria move?

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

How do bacterial cells respond to chemical gradients?

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

What is the purpose of tumbles in bacterial movement?

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

How do phototrophic bacteria optimize photosynthesis?

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

How do bacterial cells sense chemical gradients?

<p>By sampling the concentration and comparing to previous values (C)</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 (B)</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 (D)</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 (A)</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 (C)</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 (A)</p> Signup and view all the answers

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

<p>Upwards of 50 genes (B)</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 (C)</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 (D)</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 (D)</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 (A)</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 (B)</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) (A)</p> Signup and view all the answers

What is the minimum temperature that some endospores can withstand?

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

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

<p>Endospore (B)</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 (B)</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 (C)</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 (A)</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 (A)</p> Signup and view all the answers

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

<p>Helical charges (B)</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 (A)</p> Signup and view all the answers

What is the primary function of the flagellum?

<p>Swimming motility (D)</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 (B)</p> Signup and view all the answers

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

<p>Osmotaxis (D)</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 (A)</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 (A)</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 (C)</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 (D)</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 (C)</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 (D)</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 (D)</p> Signup and view all the answers

What is the primary function of chemotaxis in bacterial cells?

<p>To respond to chemical gradients (C)</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 (B)</p> Signup and view all the answers

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

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

How do phototrophic bacteria optimize photosynthesis?

<p>By positioning themselves in optimal light conditions (B)</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 (C)</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 (C)</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 (A)</p> Signup and view all the answers

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

<p>To facilitate gliding motility (B)</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 (D)</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 (A)</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 (B)</p> Signup and view all the answers

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

<p>Dysbiosis (B)</p> Signup and view all the answers

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

<p>Essential to human health (A)</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 (C)</p> Signup and view all the answers

What is the approximate pH of the stomach?

<p>2 (B)</p> Signup and view all the answers

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

<p>Biofilm (D)</p> Signup and view all the answers

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