70 Questions
What is the primary source of ethanolamine in the gut?
Plant and animal cell membranes
Which of the following bacteria utilizes EUT for growth?
All of the above
What is the term for the time required for a population of microbial cells to double?
Generation time
What is the process of cell division in which new cell material is produced from a single point?
Budding
In which phase of microbial growth does cell growth slow down due to nutrient depletion or waste buildup?
Stationary phase
What is the term for the process of microbial cells remaining alive for months despite being in a dormant state?
Death phase
What is the primary function of the slime layer and capsule on the bacterial cell surface?
To aid in attachment to solid surfaces and prevent dehydration
What is the primary function of fimbriae in bacterial cells?
To enable cells to stick to surfaces including animal tissues
What is the primary function of pili in gram-negative bacteria?
To enable genetic exchange through horizontal gene transfer
What is the primary function of the lipopolysaccharide layer in gram-negative bacteria?
To simulate CD14 and trigger immune response
What is the primary function of gram-negative secretion systems?
To enable the secretion of molecules from the cell interior to its exterior
What is the primary function of commensal bacteria in the context of inflammatory endocytosis?
To prevent inflammatory endocytosis
What is the primary function of dipicolinic acid in endospores?
It dehydrates the spores and protects DNA from denaturing
What triggers the formation of endospores in Bacillus?
Lack of nutrients such as carbon or nitrogen
What is the role of small acid-soluble spore proteins (SASPs) in endospores?
They bind to DNA
What is the minimum temperature that some endospores can withstand?
150 degrees C
What is the result of outgrowth in the life cycle of an endospore-forming bacteria?
Emergence of a vegetative cell
What is the primary mode of dispersal of endospores?
Through wind, water, and animal gut (faeces)
What is the primary mechanism by which cyanobacteria move?
Polysaccharide slime secretion
How do bacterial cells respond to chemical gradients?
By changing their movement patterns
What is the purpose of tumbles in bacterial movement?
To change direction randomly
How do phototrophic bacteria optimize photosynthesis?
By positioning themselves in optimal light conditions
How do bacterial cells sense chemical gradients?
By sampling the concentration and comparing to previous values
What is the role of the signalling and gene regulatory network in chemotaxis?
To implement the 'memory' of previous concentrations
What is the primary component of the flagellum motor that anchors it to the cytoplasmic membrane and cell wall?
Central rod
What is the direction of growth for the flagella filament in Escherichia and Salmonella?
From the tip to the base
What is the mechanism by which proton translocation through Mot proteins exerts force on the rotor proteins?
Electrostatic forces on helically arranged charges
What is the term for the type of flagellation in which flagella are located in many places around the surface of the cell?
Peritrichous flagellation
How many genes are involved in flagella biosynthesis in Escherichia and Salmonella?
Upwards of 50 genes
What is the function of the Mot proteins in the flagellum motor?
They surround the inner rings and form the stator
What is the primary reason why endospores are highly heat-resistant?
Because of the unique substance dipicolinic acid that confers heat resistance
What is the event that triggers the activation of spores in Bacillus?
When spores are heated for several minutes
What is the primary role of small acid-soluble spore proteins (SASPs) in endospores?
To bind to DNA and protect it from denaturation
What is the final stage of the life cycle of an endospore-forming bacteria?
Vegetative cell growth
What is the primary mode of dispersal of endospores?
Easily dispersed by wind, water, or animal gut (faeces)
What is the minimum temperature that some endospores can withstand?
150°C
What is the event that occurs after the spore is activated and exposed to certain nutrients?
Germination
What is the term for the survival structure produced by certain gram-positive bacteria?
Endospore
What is the term for the type of flagellation in which flagella are located at one pole of the cell?
Polar flagellation
What is the primary component of the flagellum motor that anchors it to the cytoplasmic membrane and cell wall?
Basal body
In which bacteria is the flagella filament known to grow from the tip?
E. coli and Salmonella
What is the primary function of the Mot proteins in the flagellum motor?
To surround the inner rings
What is the term for the helically arranged charges on the rotor proteins?
Helical charges
What is the primary function of the L ring and P ring in the flagellum motor?
To anchor the motor to the outer membrane and peptidoglycan layer
What is the primary function of the flagellum?
Swimming motility
What is the number of genes involved in flagella biosynthesis in Escherichia and Salmonella?
Upwards of 50
Which type of taxis involves movement towards or away from ionic strength?
Osmotaxis
What is the primary function of the sensor kinase protein in a two-component system?
To phosphorylate itself in response to an external signal
What is the purpose of quorum sensing in Vibrio cholerae?
To monitor the population level and secrete virulence factors at low population density
What is the role of the response regulator protein in a two-component system?
To bind to DNA
What is the purpose of the two-component system in bacterial cells?
To regulate gene expression based on environmental fluctuations
What is the primary mechanism by which bacteria respond to changes in chemical gradients?
Sensing temporal differences in concentration
What is the function of autoinducers AI-2 and CAI-1 in quorum sensing?
To increase the secretion of virulence factors
What is the role of the signalling and gene regulatory network in chemotaxis?
To implement the 'memory' of the bacterial cell
What is the primary function of chemotaxis in bacterial cells?
To respond to chemical gradients
What is the role of the sensor kinase protein in a two-component system?
To receive signals from the environment and phosphorylate itself
What is the purpose of the 'tumbles' in bacterial movement?
To change direction randomly
How do phototrophic bacteria optimize photosynthesis?
By positioning themselves in optimal light conditions
What is the mechanism by which bacterial cells move towards a chemical attractant?
By increasing the length of runs
What is the term for the directed movement of an organism in response to a chemical gradient?
Chemotaxis
How do bacterial cells respond to the presence of a chemical attractant?
By increasing the length of runs
What is the purpose of the polysaccharide slime secreted by cyanobacteria?
To facilitate gliding motility
What is the term used to describe the growth of microbial cells attached to a surface?
Biofilm formation
Which of the following regions of the GI tract has the highest concentration of microbial cells per gram of tissue?
Colon
What is the primary function of butyrate produced by microorganisms in the colon?
Energy source for colonic epithelial cells
What term describes an imbalance in the composition of the microbiota, leading to disease?
Dysbiosis
What is the primary role of the gut microbiome in human health?
Essential to human health
What is the term used to describe the complex carbohydrates that are digested by the gut microbiome?
Fibre
What is the approximate pH of the stomach?
2
What is the term used to describe the attached polysaccharide matrix with embedded bacterial cells?
Biofilm
Test your knowledge of bacterial cell walls, surface structures, cell inclusions, cell division, and endospores. Learn about the differences between Gram positive and Gram negative bacteria, bacterial growth, and more.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
