Bacterial Classification
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Bacterial Classification

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Questions and Answers

What is the primary function of selective media?

  • To identify bacteria based on pigment production
  • To differentiate bacteria based on enzyme activity
  • To reduce the numbers of irrelevant bacteria in samples (correct)
  • To allow the growth of all bacteria equally
  • What does the oxidase test differentiate between?

  • Presence or absence of cytochrome C (correct)
  • Gram-positive and gram-negative organisms
  • Presence or absence of antibiotic resistance
  • Growth patterns on selective media
  • Which term describes antibody reactions with specific bacterial cell structures?

  • Plasmids
  • Sero (correct)
  • Genomes
  • Bacteriophages
  • What does genetic instability in bacteria refer to?

    <p>Variable traits possibly caused by plasmids</p> Signup and view all the answers

    How do bacteria typically reproduce?

    <p>By binary fission</p> Signup and view all the answers

    What is suggested by phylogenetic classification in bacteria?

    <p>Shared ancestors between organisms</p> Signup and view all the answers

    What is the significance of chemical characterization of bacterial genomic DNA?

    <p>It measures genetic relatedness among organisms</p> Signup and view all the answers

    What challenge does the fossil record pose in bacterial classification?

    <p>It lacks evidence for determining bacterial evolution</p> Signup and view all the answers

    Which type of bacteria is characterized by the presence of a peptidoglycan cell wall?

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

    What technique is noted for providing a more precise method for species delineation in bacteria?

    <p>DNA sequencing</p> Signup and view all the answers

    What characteristic is unique to the membranes of Mollicutes?

    <p>Requirement for cholesterol for growth</p> Signup and view all the answers

    Which of the following is a basic type of Archaebacteria?

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

    Which process do Gram-positive bacteria primarily use for reproduction?

    <p>Binary fission</p> Signup and view all the answers

    Which type of prokaryotic cell resembles eukaryotic cells and lacks a classic peptidoglycan cell wall?

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

    What is the primary purpose of serologic typing in epidemiology?

    <p>To identify bacterial strains via antigenic differences</p> Signup and view all the answers

    Which of the following is NOT a form of reproduction in bacteria?

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

    What role do monoclonal antibodies play in subtyping microorganisms?

    <p>They provide a means to create standardized subtyping systems.</p> Signup and view all the answers

    What is the purpose of multilocus enzyme electrophoresis (MLEE) in genotyping?

    <p>To investigate the mobility of soluble enzymes in relation to genetic diversity</p> Signup and view all the answers

    What characteristic is associated with Gram-negative eubacteria?

    <p>Complex cell envelope</p> Signup and view all the answers

    Which feature distinguishes Archaebacteria from eubacteria?

    <p>Presence of isoprenoid diether or diglycerol tetraether lipids</p> Signup and view all the answers

    Mycoplasmas can be described as which of the following?

    <p>Enclosed by a plasma membrane</p> Signup and view all the answers

    Which bacterial group includes species that can be phototrophic or nonphototrophic?

    <p>Gram-negative eubacteria</p> Signup and view all the answers

    What is subtyping in the context of bacteriology?

    <p>The process of distinguishing bacteria within the same species</p> Signup and view all the answers

    Why is identifying the E coli serotype O157:H7 important?

    <p>It is key to preventing foodborne illness outbreaks.</p> Signup and view all the answers

    What is primarily improved through chemical fingerprinting?

    <p>Isolate identification using physical methods</p> Signup and view all the answers

    What technique is NOT associated with nucleic acid-based taxonomy?

    <p>GC-MS (Gas Chromatography-Mass Spectrometry)</p> Signup and view all the answers

    Which method is most useful for examining temporal and spatial outbreaks?

    <p>Restriction endonuclease analysis</p> Signup and view all the answers

    What is the primary function of restriction endonucleases?

    <p>To cleave DNA at specific sites</p> Signup and view all the answers

    Which analysis method detects polymorphisms of rRNA genes in bacteria?

    <p>Southern blot analysis</p> Signup and view all the answers

    What subtyping method uses the concept of restriction fragment length polymorphisms (RFLPs)?

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

    Which technique is involved in separating plasmids from bacteria?

    <p>Agarose gel electrophoresis</p> Signup and view all the answers

    What characteristic of restriction endonucleases contributes to their utility in analysis?

    <p>They recognize specific short DNA sequences.</p> Signup and view all the answers

    What is a primary limitation of ribotyping for certain microorganisms?

    <p>Some organisms like mycobacteria have only a single copy of ribosomal genes.</p> Signup and view all the answers

    What does the PCR-assisted approach involving rRNA primarily help identify?

    <p>Previously uncharacterized pathogenic microorganisms.</p> Signup and view all the answers

    How many bacterial species are estimated to exist in the world according to recent studies?

    <p>Between 10 million and 1 billion.</p> Signup and view all the answers

    What role do bioinformatical tools play in microbial genome sequencing?

    <p>They help identify novel targets for pathogen subtyping.</p> Signup and view all the answers

    What application does multiple-locus VNTR analysis (MLVA) primarily serve?

    <p>Subtyping monomorphic species like Bacillus anthracis.</p> Signup and view all the answers

    Which method is commonly used in microbial forensics to address epidemiologic questions?

    <p>Identifying single nucleotide polymorphisms (SNPs).</p> Signup and view all the answers

    What is one challenge faced in estimating total numbers of organisms in microbial studies?

    <p>Detection and recovery difficulties in sampling.</p> Signup and view all the answers

    What pathogen was identified as causing bacillary angiomatosis using modern techniques?

    <p>Bartonella henselae</p> Signup and view all the answers

    Study Notes

    Media Types in Bacterial Growth

    • Blood Agar and Chocolate Agar: Essential media types for bacterial cultivation.
    • Selective Media: Designed to reduce non-relevant bacterial populations from samples.
    • Differential Media: Allows differentiation based on pigmentation and extracellular enzymes.

    Bacterial Classification

    • Microscopy Techniques:
      • Gram Stain: Essential for classification based on cell wall properties.
      • Light Microscopy: Used for observing bacterial structure.

    Biochemical Testing

    • Oxidase Test: Identifies organisms based on the presence of cytochrome C.
    • Catalase Activity: Differentiates gram-positive from gram-negative cocci.

    Immunological Tests

    • Sero-based Classification: Utilizes antibodies reacting with bacterial structures for classification into serotypes, serogroups, and serovars.

    Genetic Instability

    • Defining Taxonomic Groups: Genetic traits can indicate shared characteristics or instability within a biological group.
    • Resistance Genes: Often located on plasmids affecting bacterial adaptability.

    Phylogenetic Classification

    • Indicates shared ancestry among organisms; lacks fossil evidence complicates distinguishing evolutionary paths.

    Genetic Diversity Among Bacteria

    • Nucleotide Base Composition: Variability within genomic DNA characterizes different species.
    • DNA Sequencing: A precise tool for species identification.
    • Bergey's Manual: Major taxonomic reference for bacteria published in 1923.

    Types of Prokaryotic Organisms

    • Eubacteria: Characterized by peptidoglycan cell walls and diverse metabolic types, including phototrophic and nonphototrophic organisms.
    • Archaebacteria: Lacks peptidoglycan but shares some eukaryotic cell features.

    Gram-Negative and Gram-Positive Eubacteria

    • Gram-Negative: Complex cell envelope; capable of various respiration types.
    • Gram-Positive: Thick cell wall structure, may produce spores for survival.

    Eubacteria Lacking Cell Walls

    • Mycoplasmas: Small bacteria without cell walls, require cholesterol for growth, reproduce through various methods including budding.

    Archaebacteria

    • Extremophiles: Residing in extreme environments with unique cellular structures and metabolic pathways.

    Subtyping Bacterial Strains

    • Characteristics for Discrimination: Can identify strains below species level using various methods such as serotyping.

    Serologic Typing and Epidemiology

    • Valuable in tracking infectious disease outbreaks, enhanced by biotechnology.

    Genotyping Techniques

    • Multilocus Enzyme Electrophoresis (MLEE): Standard for analyzing genetic diversity in microorganisms.

    Chemical Fingerprinting Methods

    • Techniques such as FTIR and mass spectrometry facilitate accurate isolate identification.

    Nucleic Acid-Based Taxonomy

    • Techniques: Plasmid profile analysis and ribotyping for subtype identification.

    Plasmid Analysis

    • Involves isolation and separation of plasmids through gel electrophoresis to trace bacterial outbreaks.

    Restriction Endonuclease Analysis

    • DNA cleavage method for subtyping through agarose gel electrophoresis and pulsed field gel electrophoresis.

    Southern Blot Analysis

    • Identifies isolates associated with outbreaks through DNA fragment analysis.

    Ribotyping

    • Detects polymorphisms in ribosomal RNA genes, revealing genetic relationships among bacteria.

    Repetitive Sequences in Microbial Genomes

    • Multiple-locus VNTR Analysis (MLVA): PCR-based subtyping for identifying bacterial strains.

    Microbial Forensics

    • Advanced genotyping methods emerging to tackle epidemiological challenges and investigate bioterrorism.

    Non-Culture Methods for Pathogen Identification

    • PCR-Assisted Techniques: Identify pathogens directly in situ and have led to the discovery of new bacterial species.

    Bacterial Species Estimate

    • Recent studies suggest total bacterial species count ranges between 10^7 and 10^9, highlighting biodiversity challenges.

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    Description

    This quiz explores the principles of bacterial classification and growth, focusing on selective and differential media, as well as microscopy techniques like Gram staining. Test your knowledge on biochemical tests and the characteristics of various bacteria when cultured. Prepare to dive deep into the fascinating world of microbiology!

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