194 Questions
Who is often credited as the first person to observe microorganisms using a microscope?
Van Leeuwenhoek
Which scientist's work laid the groundwork for the idea of a hidden world of tiny living organisms not visible to the naked eye?
Van Leeuwenhoek
Who is considered a pioneer of antiseptic procedures and worked as an obstetrician in Vienna?
Semmelweis
Who claimed that diseases, like plants and animals, have 'invisible seeds'?
Akshamsaddin
What is the basis for the evidence supporting the two-domain system in microbiology?
Genetic information, particularly ribosomal RNA sequences
Which microscopy technique is used to improve contrast by illuminating the specimen against a dark background?
Dark-field microscopy
What is the main factor contributing to total magnification in a light microscope?
Product of ocular and objective lens powers
In a bright-field microscope, what is the function of the condenser lens?
To focus light onto the specimen
What distinguishes helminths and viruses as part of microbiology?
Their impact on infectious diseases
"What differentiates bright-field and dark-field light microscopy?"
Image contrast and background illumination
"What defines the key differences between Bacteria and Archaea?"
Cell wall composition, lipids in membrane, and genetic differences.
"Which organisms are outlined based on their defining features, roles, and characteristics?"
Fungi, protozoa, and helminths.
"What are non-microbes such as helminths and viruses considered part of microbiology?"
Due to their impact on infectious diseases.
"What is explained through definitions of magnification, refraction, resolution, and contrast in microscopy?"
Key concepts relevant to microscopy techniques.
"What are techniques used to improve contrast in microscopy?"
Dark-field, phase contrast, and differential interference.
Who pioneered antiseptic surgery with the use of carbolic acid?
Lister
Which scientist observed higher patient mortality in doctor-run clinics than midwife-run clinics?
Semmelweis
Who demonstrated that microbes can cause disease by isolating a fungus that killed silkworms?
Bassi
Which scientist developed postulates to establish a causal relationship between microbes and disease?
Koch
Who disproved spontaneous generation and developed techniques for vaccine production?
Pasteur
Which scientist discovered the causes of anthrax, cholera, and tuberculosis?
Pasteur
What is the technique used to detect unique proteins in microbes?
Fluorescent compound tagging via antibodies
Which bacterial cell shape is classified as cylindrical?
Bacilli
What are the groupings of prokaryotes after binary fission?
Diplococcus, long chains, cubical packets, grapelike clusters
What allows passage of amino acids and simple sugars in gram-negative bacteria?
Outer membrane with porins
What is the basic structure of LPS (lipopolysaccharide)?
$Lipid A$, core polysaccharide, and O antigen
Which component of LPS is recognized by the immune system?
Lipid A
What is the function of O antigen in LPS?
It helps identify bacterial species or strains
What is the unique pattern of sugars between Lipid A and O antigen in LPS?
Core polysaccharide
What do bacterial transport processes include?
Diffusion, passive transport, active transport, facilitated transport
What do prokaryotes use for active movement of proteins out of the cell?
Extracellular enzymes and external structures
What is the resolution limit for light microscopy due to visible light's physical constraints?
0.2 nanometers
Which microscopy technique observes cell structure details by directing electrons through or scattering them within the specimen?
Transmission EM
What distinguishes the Gram stain from other staining techniques?
It distinguishes gram-positive and gram-negative bacteria
Which staining technique detects mycobacteria with high mycolic acid concentrations?
Acid-fast stain
What is the main drawback of electron microscopy compared to light microscopy?
Expensive and complex to operate
What distinguishes immunofluorescence from fluorescence microscopy?
It attaches fluorescent molecules to antibodies for simultaneous visualization of different cellular components emitting different colors
What does dark-field microscopy achieve by directing light at an angle?
Creating bright cell images against a dark background
Which staining technique distinguishes cell types rather than simple staining involving a single dye?
Differential staining
What is the primary drawback of fluorescence microscopes compared to bright-field microscopes?
Complex and expensive to operate
What does scanning EM do to yield a three-dimensional effect?
Coats the specimen surface with a thin metal film and scans it with an electron beam
What is the primary advantage of electron microscopes over light microscopes in terms of visualization?
Higher magnification and detailed visualization capabilities
What is the resolution limit of light microscopy due to visible light's physical constraints?
0.2 nanometers
Which microscopy technique uses electromagnetic lenses and electrons for visualization?
Electron microscopy
What staining technique distinguishes gram-positive and gram-negative bacteria?
Gram stain
Which staining method is used to detect mycobacteria with high mycolic acid concentrations?
Acid-fast stain
What type of microscopy provides powerful cellular component visualization using fluorophores?
Fluorescence microscopy
$f(x) = -4(x + 3)^2 + 2$. What is the vertex of this quadratic function?
Not a valid question for this context
Who coined the term 'virus' to describe a filterable infectious agent?
Beijerink
What did Ivanovsky identify as the first virus discovered?
Tobacco mosaic virus
What is the smallest virus known, requiring only two genes to replicate and produce viruses?
Parvovirus
What did Loeffler and Frosch discover is caused by a virus?
Foot-and-mouth disease in cattle
Which bacterial cell shape is classified as spherical?
Cocci
What is the most conserved component of LPS recognized by the immune system?
Lipid A
Which bacterial cell structure consists of NAG-NAM chains and wall peptides?
Peptidoglycan
What type of bacteria have an outer membrane with porins allowing passage of AAs and simple sugars?
Gram-negative bacteria
What are the groupings of prokaryotes after binary fission called?
Diplococcus, long chains, cubical packets, and grapelike clusters
What are the examples of bacterial cell shapes classified as cylindrical?
E. coli, listeria, and salmonella
What is the basic structure of LPS (lipopolysaccharide) that can cause symptoms characteristic of bacterial infection?
Lipid A, core polysaccharide, and O antigen
What helps identify bacterial species or strains and varies in number and type of sugar molecules?
O antigen
What is a unique pattern of sugars between Lipid A and O antigen in LPS (lipopolysaccharide)?
Core polysaccharide
What do gram-positive bacteria have that gram-negative bacteria lack in their cell wall structure?
Thick peptidoglycan cell wall
Which viral infection life cycle stage involves the release of new virions from the host cell?
Release
Which virus causes both chickenpox and shingles, residing in nerve cells?
Herpes virus
What is the primary location for DNA virus replication within the host cell?
Host cell nucleus
What is the term for visible damage to host cells caused by viral infection, manifesting as cell rounding, fusion, or death?
Viral cytopathic effect (CPE)
Which type of infection involves periods of inactivity followed by reactivation?
'Latent infection'
What is the primary difference between enveloped and non-enveloped viruses?
Presence of lipid envelopes
Which type of virus can contribute to cancer by integrating its genetic material into the host cell's DNA?
HPV (Human Papillomavirus)
What is a virion?
The complete infectious viral particle outside a host cell
Where do RNA viruses primarily replicate within the host cell?
Host cell cytoplasm
What distinguishes acute infections from persistent infections?
Duration of infection
'What is a defining characteristic of eukaryotic cells?'
'Presence of a true nucleus and membrane-bound organelles'
Which of the following is a characteristic used for classifying viruses?
Presence of lipid envelopes
What distinguishes acute infections from persistent infections?
Duration of the infection
Where do DNA viruses often replicate within the host cell?
Nucleus
What is the function of a virion?
To be a complete infectious viral particle outside a host cell
What contributes to cytopathic effect (CPE) in viral infections?
Visible damage to host cells caused by viral infection
What distinguishes eukaryotic cells from prokaryotic cells?
The presence of a true nucleus and membrane-bound organelles
Which virus can cause both chickenpox and shingles?
Varicella-Zoster virus
What can some viruses contribute to by integrating their genetic material into the host cell's DNA?
Cancer development
What is the term for periods of inactivity followed by reactivation in viral infections?
Latent infections
Where do RNA viruses often replicate within the host cell?
Cytoplasm
Which pathogen causes a gastrointestinal illness through waterborne transmission?
Cryptosporidium
What is the primary mode of transmission for Toxoplasma gondii?
Contaminated food
Which bacterium has a preference for high salt environments?
Halophile
What distinguishes facultative anaerobes from obligate anaerobes?
Ability to grow with or without oxygen
What is the function of catalase in microbial cells?
Breaks down hydrogen peroxide
What is the primary goal of pasteurization in the context of food and beverages?
Eliminates pathogens
What is the primary advantage of WGS (Whole Genome Sequencing) in microbial genomics?
High resolution and detailed genomic information
What is the therapeutic index of a drug?
A ratio comparing the dose causing toxic effect to the dose causing therapeutic effect
Which antimicrobial drugs inhibit nucleic acid synthesis?
Fluoroquinolones and rifamycins
How is the minimum inhibitory concentration (MIC) determined?
It is the lowest concentration of an antimicrobial agent that inhibits visible growth of a microorganism
What are four general mechanisms of antimicrobial resistance?
Drug inactivation/enzyme modification, alteration in target molecule, decreased uptake of the drug, increased elimination of the drug
What is the primary purpose of chemical preservatives in microbial preservation?
To inhibit microbial growth and extend shelf life
How are prokaryotes primarily identified in microbiology?
Through microscopic morphology, culture characteristics, and metabolic capabilities
What do biofilms in microbiology refer to?
Communities of microorganisms resistant to antibiotics and immune responses
What is the primary method for distinguishing different strains of microorganisms?
Biochemical tests, serological typing, and molecular typing
Which methods are used to classify prokaryotes?
$16S$ rRNA sequencing, serological typing, and MLST
What is the definition of a species in microbiology?
A group of organisms capable of interbreeding
What does reducing water availability achieve in microbial preservation?
Inhibits microbial growth
What aids in the identification of prokaryotes?
Phenotypic characteristics like microscopic morphology and metabolic capabilities
What is the primary purpose of low-temperature storage in food preservation?
Slows microbial growth and preserves food
How can prokaryotes be classified?
Using morphology, immunological methods, and molecular techniques
What is the definition of a strain in microbiology?
A group of microorganisms derived from a single original isolate
What is the primary purpose of chemical preservatives in microbial preservation?
To inhibit microbial growth and extend shelf life
How are prokaryotes primarily identified in microbiology?
Through microscopic morphology, culture characteristics, and metabolic capabilities
What do biofilms in microbiology refer to?
Communities of microorganisms resistant to antibiotics and immune responses
What is the primary method for distinguishing different strains of microorganisms?
Biochemical tests, serological typing, and molecular typing
Which methods are used to classify prokaryotes?
$16S$ rRNA sequencing, serological typing, and MLST
What is the definition of a species in microbiology?
A group of organisms capable of interbreeding
What does reducing water availability achieve in microbial preservation?
Inhibits microbial growth
What aids in the identification of prokaryotes?
Phenotypic characteristics like microscopic morphology and metabolic capabilities
What is the primary purpose of low-temperature storage in food preservation?
Slows microbial growth and preserves food
How can prokaryotes be classified?
Using morphology, immunological methods, and molecular techniques
What is the definition of a strain in microbiology?
A group of microorganisms derived from a single original isolate
What is the primary method used to inhibit microbial growth and extend shelf life?
Chemical preservatives
In microbiology, what defines a group of microorganisms capable of interbreeding?
Species
How are prokaryotes primarily identified?
Microscopic morphology
What aids in the identification of prokaryotes?
$16S$ rRNA sequencing
Which method is used to classify prokaryotes?
$16S$ rRNA sequencing
What is a strain in microbiology?
A group of microorganisms derived from a single original isolate
What aids in distinguishing different strains of microorganisms?
All of the above
Which method is used to classify both species and strains?
16S rRNA sequencing
What are biofilms in microbiology?
Communities of microorganisms resistant to antibiotics and immune responses
What is a common method used to slow microbial growth and preserve food?
Low-temperature storage
Which characteristic aids in the identification of prokaryotes?
All of the above
Which microorganism causes toxoplasmosis and is transmitted by contaminated food or cat feces?
Toxoplasma gondii
What is the primary method of transmission for Cryptosporidium, causing gastrointestinal illness?
Waterborne transmission
Which enzyme breaks down hydrogen peroxide, a characteristic of many microorganisms?
Catalase
What is the distinguishing characteristic of facultative anaerobes among microbial pathogens?
They can grow with or without oxygen
Which bacteria have different temperature and pH preferences, reflecting their adaptability?
Mesophile, thermophile, hyperthermophile
'Sterilization' in microbiology refers to:
Eradicating all microbial life
What is the distinguishing feature of obligate anaerobes among microbial pathogens?
They cannot survive in the presence of oxygen.
What type of infection involves periods of inactivity followed by reactivation?
Latent infection.
What is the primary function of pasteurization in relation to food and beverages?
Treating food and beverages.
Which amoeba causes a fatal brain infection and is found in warm freshwater?
Naegleria fowleri.
What type of bacteria can grow with or without oxygen?
Facultative anaerobes.
What is the characteristic feature of tapeworm transmission to humans?
Ingesting contaminated food/water.
What is the minimum inhibitory concentration (MIC)?
The lowest concentration of an antimicrobial agent that inhibits visible growth of a microorganism.
What is the therapeutic index of a drug?
The ratio comparing the dose that causes a toxic effect to the dose that causes a therapeutic effect.
Which mechanism of antimicrobial resistance involves altering the target molecule?
Alteration in target molecule.
What distinguishes Kirby-Bauer disc diffusion test from commercial modifications of antimicrobial susceptibility testing?
Commercial modifications use paper discs impregnated with antimicrobial agents to test susceptibility.
"Cidal" drugs are those that:
Kill the microorganisms.
What is selective toxicity?
The ability of an antimicrobial agent to selectively target and inhibit or kill the pathogen without causing significant harm to the host.
How are ß-lactam drugs and other antimicrobials related?
Both ß-lactam drugs and other antimicrobials inhibit cell wall synthesis.
What does acquired resistance to specific drugs result from?
Both A and B are correct.
How can the emergence and spread of antimicrobial resistance be slowed?
By proper use of antimicrobials, combination therapy, global cooperation, public education, surveillance, and monitoring.
What economic factors are slowing the development of new drugs?
Both A and B are correct.
What species primarily produce antibiotics?
Both bacteria and fungi are correct.
Which pathogen causes a fatal brain infection and is found in warm freshwater?
Naegleria fowleri
What is the primary mode of transmission for Toxoplasma gondii?
Contaminated food or cat feces
Which enzyme breaks down hydrogen peroxide in microbial cells?
Catalase
What is the primary function of pasteurization in the context of food and beverages?
Treats food and beverages
What type of bacteria can grow with or without oxygen?
Facultative anaerobes
What is the primary difference between sterilization and disinfection?
Sterilization eliminates all microbial life, while disinfection reduces pathogens on surfaces.
What is the function of superoxide dismutase in microbial cells?
Converts superoxide radicals into hydrogen peroxide and oxygen.
Which organism causes candidiasis and is multidrug-resistant?
Candida auris
What does preservation aim to do in the context of microbial control?
Inhibits microbial growth
What is the primary mode of transmission for various tapeworm species?
Ingesting undercooked meat
Which organism causes gastrointestinal illness through waterborne transmission?
Cryptosporidium
What is the primary method used to inhibit microbial growth and extend shelf life?
Chemical preservatives
In microbiology, what defines a group of microorganisms capable of interbreeding?
Species
How are prokaryotes primarily identified?
Microscopic morphology
What aids in the identification of prokaryotes?
$16S$ rRNA sequencing
Which method is used to classify prokaryotes?
$16S$ rRNA sequencing
What is a strain in microbiology?
A group of microorganisms derived from a single original isolate
What aids in distinguishing different strains of microorganisms?
All of the above
Which method is used to classify both species and strains?
16S rRNA sequencing
What are biofilms in microbiology?
Communities of microorganisms resistant to antibiotics and immune responses
What is a common method used to slow microbial growth and preserve food?
Low-temperature storage
Which characteristic aids in the identification of prokaryotes?
All of the above
Which type of infection involves periods of inactivity followed by reactivation?
Latent infection
What is a virion?
An infectious viral particle outside a host cell
What distinguishes enveloped viruses from non-enveloped viruses?
Presence of lipid envelopes
Where do DNA viruses often replicate within the host cell?
Nucleus
$f(x) = -4(x + 3)^2 + 2$. What is the vertex of this quadratic function?
$(-3, 2)$
What is the primary location for RNA virus replication within the host cell?
Cytoplasm
What is the term for visible damage to host cells caused by viral infection?
Cytopathic effect (CPE)
Which virus causes both chickenpox and shingles, residing in nerve cells?
Varicella-Zoster virus
What contributes to cancer by integrating its genetic material into the host cell's DNA?
HPV
What distinguishes eukaryotic cells from prokaryotic cells?
Presence of membrane-bound organelles
What is the primary difference between acute infections and persistent infections?
Duration of virus presence
What is the primary advantage of whole genome sequencing (WGS)?
High resolution and detailed genomic information
What is the therapeutic index of a drug?
The ratio comparing the dose causing toxic effects to the dose causing therapeutic effects
Which antimicrobial drug inhibits nucleic acid synthesis?
Fluoroquinolones
How is the minimum bactericidal concentration (MBC) determined?
It is the lowest concentration killing 99.9% of bacterial cells
"Cidal" drugs are those that:
Kill microorganisms
What defines acquired resistance to antimicrobials?
Results from genetic changes or acquisition of resistance genes
What is a key factor slowing the development of new antibiotics?
The challenge of overcoming resistance and finding novel targets
What is the primary purpose of combination therapy in antimicrobial treatment?
To broaden the spectrum of activity and increase efficacy
How are commercial modifications different from Kirby-Bauer disc diffusion test for antimicrobial susceptibility testing?
Commercial modifications involve automated systems for more precise measurements, while Kirby-Bauer uses paper discs impregnated with antimicrobial agents for testing susceptibility.
What defines selective toxicity in the context of antimicrobial agents?
The ability to selectively target and inhibit or kill the pathogen without causing significant harm to the host.
What species primarily produce antibiotics?
Bacteria and fungi
Study Notes
Bacterial Cell Structures and Transport Processes
- Technique using fluorescent compound tagging via antibodies to detect unique proteins in microbes
- Bacterial cell shapes classified as cocci (spherical) and bacilli (cylindrical), with examples like E. coli, listeria, and salmonella
- Groupings of prokaryotes after binary fission, including diplococcus, long chains, cubical packets, and grapelike clusters
- Different transport systems for molecules across the cell membrane, including facilitated diffusion, active transport, and protein secretion
- Gram-negative bacteria have an outer membrane with porins allowing passage of AAs and simple sugars, while gram-positive bacteria have a thick peptidoglycan cell wall
- Peptidoglycan structure consisting of NAG-NAM chains and wall peptides forming glycan chains and tetrapeptide chains
- Basic structure of LPS (lipopolysaccharide) including Lipid A, core polysaccharide, and O antigen, which can cause symptoms characteristic of bacterial infection and help bacteria evade the immune system
- Lipid A is the most conserved component of LPS and is recognized by the immune system
- O antigen helps identify bacterial species or strains and varies in number and type of sugar molecules
- Core polysaccharide is a unique pattern of sugars between Lipid A and O antigen
- Bacterial transport processes include diffusion, passive transport, active transport, and facilitated transport
- Prokaryotes use a variety of secretion systems for active movement of proteins out of the cell, such as extracellular enzymes and external structures
Viral Classification, Infections, and Eukaryotic Microbes Overview
- Viruses are classified based on nucleic acid type, envelope presence, capsid symmetry, and virion dimensions.
- Viruses are challenging to study in the lab because they require a host cell for replication and are intracellular parasites.
- Enveloped viruses have lipid envelopes, examples include Influenza and Herpes; non-enveloped viruses lack lipid envelopes, examples include Adenovirus and Tobacco Mosaic Virus.
- Varicella-Zoster virus causes both chickenpox and shingles, residing in nerve cells.
- Acute infections are short-lived with rapid onset, while persistent infections last an extended period, divided into chronic and latent types.
- Some viruses can contribute to cancer by integrating their genetic material into the host cell's DNA, examples include HPV and Hepatitis B and C viruses.
- A virion is a complete, infectious viral particle outside a host cell, consisting of the viral genome and a protective protein coat.
- The viral infection life cycle involves attachment, penetration, synthesis, assembly, and release.
- DNA viruses often replicate in the host cell nucleus, while RNA viruses replicate in the cytoplasm; retroviruses use reverse transcription.
- Latent infections have periods of inactivity followed by reactivation, acute infections are short-lived, and chronic infections involve continual virus production.
- Cytopathic effect (CPE) refers to visible damage to host cells caused by viral infection, manifesting as cell rounding, fusion, or death.
- Eukaryotic cells have a true nucleus and membrane-bound organelles, while prokaryotic cells lack a true nucleus and membrane-bound organelles.
Viral Classification, Infections, and Eukaryotic Microbes Overview
- Viruses are classified based on nucleic acid type, envelope presence, capsid symmetry, and virion dimensions.
- Viruses are challenging to study in the lab because they require a host cell for replication and are intracellular parasites.
- Enveloped viruses have lipid envelopes, examples include Influenza and Herpes; non-enveloped viruses lack lipid envelopes, examples include Adenovirus and Tobacco Mosaic Virus.
- Varicella-Zoster virus causes both chickenpox and shingles, residing in nerve cells.
- Acute infections are short-lived with rapid onset, while persistent infections last an extended period, divided into chronic and latent types.
- Some viruses can contribute to cancer by integrating their genetic material into the host cell's DNA, examples include HPV and Hepatitis B and C viruses.
- A virion is a complete, infectious viral particle outside a host cell, consisting of the viral genome and a protective protein coat.
- The viral infection life cycle involves attachment, penetration, synthesis, assembly, and release.
- DNA viruses often replicate in the host cell nucleus, while RNA viruses replicate in the cytoplasm; retroviruses use reverse transcription.
- Latent infections have periods of inactivity followed by reactivation, acute infections are short-lived, and chronic infections involve continual virus production.
- Cytopathic effect (CPE) refers to visible damage to host cells caused by viral infection, manifesting as cell rounding, fusion, or death.
- Eukaryotic cells have a true nucleus and membrane-bound organelles, while prokaryotic cells lack a true nucleus and membrane-bound organelles.
Explore the various beneficial roles of microbes in biotechnology, food production, environmental processes, and medicine. Learn how microbes are utilized in different industries and contribute to important processes.
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