Introduction to Microbiology
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What is the primary function of a microscope in microbiology?

  • To study organisms that can be seen by the naked eye
  • To observe microorganisms that are too small to be seen by the naked eye (correct)
  • To study the structure of plants and animals
  • To observe the movement of particles in a fluid

    • Who is credited with being the first to observe microorganisms using a simple microscope?

  • Wael Nabil Hozzein
  • Louis Pasteur
  • Antonie van Leeuwenhoek (correct)
  • Francesco Redi

    • What is the theory that states living things can arise from vital forces present in nonliving and decaying matter?

  • Microbiology
  • Spontaneous Generation (correct)
  • Biogenesis
  • Abiogenesis

    • Who is credited with developing aseptic techniques and a rabies vaccine?

    <p>Louis Pasteur</p> Signup and view all the answers

    What is the process by which sugar is converted to alcohol to make beer and wine?

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

    What is the result of bacterial growth on wine?

    <p>Spoilage of wine to vinegar</p> Signup and view all the answers

    What is the purpose of heat in Pasteur's method of preserving wine?

    <p>To kill spoilage bacteria</p> Signup and view all the answers

    What is the term for the theory that living organisms can arise only from preexisting life forms?

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

    What is the primary goal of phylogeny or systematics?

    <p>To identify all organisms by 2025</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the kingdom Plantae?

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

    What is phage typing used for?

    <p>Determining the susceptibility of bacteria to phages</p> Signup and view all the answers

    Which domain includes organisms with unusual cell walls and membranes?

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

    What is the primary focus of chemotaxonomy?

    <p>The study of the chemical variation in microbial cells</p> Signup and view all the answers

    What is the primary function of differential staining techniques in identifying bacteria?

    <p>To determine the morphological characteristics of bacteria</p> Signup and view all the answers

    What is the significance of peptidoglycan in bacterial classification?

    <p>It provides important information for the classification of bacteria</p> Signup and view all the answers

    What is the primary function of biochemical tests in identifying bacteria?

    <p>To identify the presence of bacterial enzymes</p> Signup and view all the answers

    What is the significance of DNA fingerprinting in microbiology?

    <p>It is used to analyze the restriction enzyme digests of DNA</p> Signup and view all the answers

    What is the term for the study of evolutionary relationships and history among organisms?

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

    What is the function of the International Code for the Nomenclature of Bacteria?

    <p>To establish a universal system for naming bacteria</p> Signup and view all the answers

    What is the purpose of using dichotomous keys in identifying organisms?

    <p>To identify the specific species of an organism</p> Signup and view all the answers

    What is the primary characteristic used to identify the species of a bacterium?

    <p>Physiological characteristics</p> Signup and view all the answers

    What is the purpose of analyzing the fatty acid composition of bacterial membranes?

    <p>To identify the chemical characteristics of bacteria</p> Signup and view all the answers

    What is the purpose of analyzing the end products of bacterial metabolism?

    <p>To identify the physiological characteristics of bacteria</p> Signup and view all the answers

    What is the purpose of analyzing the structure of cell wall murein in bacteria?

    <p>To identify the chemical characteristics of bacteria</p> Signup and view all the answers

    What is the primary application of numerical taxonomy?

    <p>To carry out taxonomic work with less skilled workers</p> Signup and view all the answers

    What is the function of the Ribosomal Database Project (RDP)?

    <p>To maintain a large collection of rRNA sequences and provide analytical programs</p> Signup and view all the answers

    What is the significance of 16S rRNA gene sequences in taxonomy?

    <p>They serve as a 'gold standard' for the identification and description of new species</p> Signup and view all the answers

    What is the significance of Carl Woese's work?

    <p>He established the presence of three domains of life: Bacteria, Archaea, and Eukarya</p> Signup and view all the answers

    What is the characteristic of the 16S rRNA gene sequences used for phylogenetic studies?

    <p>They are functionally constant and change slowly</p> Signup and view all the answers

    What is the proposed threshold for considering a bacterium as a new species?

    <p>A difference of 3% in 16S rRNA gene sequence from any named strain</p> Signup and view all the answers

    What is the purpose of whole-genome sequence analyses?

    <p>To study the genome structure and composition</p> Signup and view all the answers

    What is the significance of the Domain Bacteria?

    <p>It contains at least 80 major evolutionary groups (phyla)</p> Signup and view all the answers

    Which of the following sugars is not typically associated with whole cell hydrolysate?

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

    What is the primary function of respiratory quinones in the bacterial cytoplasmic membrane?

    <p>Electron transport chain</p> Signup and view all the answers

    What is the typical carbon atom range found in fatty acids of bacterial membranes?

    <p>8-20</p> Signup and view all the answers

    Which type of lipid is NOT typically associated with bacterial plasma membranes?

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

    What is the primary characteristic of amphipathic polar lipids in bacterial plasma membranes?

    <p>Hydrophilic head groups linked to two hydrophobic fatty acid chains</p> Signup and view all the answers

    What is the significance of analyzing the quinone system in bacterial characterization?

    <p>It provides insight into the bacteria's chemotaxonomic properties</p> Signup and view all the answers

    Which of the following is a type of phosphatidylglycolipid?

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

    Which of the following sugars is typically associated with whole cell hydrolysate?

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

    Study Notes

    Introduction to Microbiology

    • Microbiology: the study of organisms too small to be seen by the naked eye, requiring a microscope
    • Microbes or microorganisms: commonly referred to as “germs” or “bugs”, include bacteria, helminths, fungi, algae, protozoa, and prions (infectious proteins)

    History of Microbiology

    • Antonie van Leeuwenhoek: first observed microbes using a simple microscope (1673) and reported his “animalcules” to the Royal Society of London
    • Francesco Redi: opposed the theory of Spontaneous Generation, showing that maggots came from flies (1668)
    • Biogenesis: the theory that life comes from life, opposed to Spontaneous Generation

    The Golden Age of Microbiology

    • Louis Pasteur (1822-1895): showed microbes caused fermentation and spoilage, disproved spontaneous generation, developed aseptic techniques, and developed a rabies vaccine
    • Fermentation and Pasteurization:
      • Microbes responsible for fermentation
      • Fermentation: conversion of sugar to alcohol to make beer and wine
      • Microbial growth responsible for spoilage of food
      • Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar

    Bacterial Taxonomy

    • Physiological characteristics:
      • Respiratory chain enzymes (oxidases, catalases)
      • Enzymes that break down carbohydrates, alcohols, glycosides (e.g., betagalactosidase)
      • Protein metabolism enzymes (e.g., gelatinase, collagenase)
      • Amino acid metabolism enzymes (e.g., decarboxylases, deaminases, urease)
    • Chemical characteristics:
      • DNA structure (base sequences)
      • Structure of cell wall murein
      • Antigen structure: fine structures detectable with antibodies
      • Fatty acids in membranes and cell wall

    Identifying Bacteria

    • Morphological characteristics: useful for identifying eukaryotes
    • Differential staining: Gram Staining, acid-fast staining
    • Biochemical tests: determines presence of bacterial enzymes
    • Dichotomous keys used for identification of organisms

    Nomenclature

    • International Code for the Nomenclature of Bacteria: sets out rules for bacterial nomenclature
    • Species designated with two Latinized names, the first characterizing the genus and the second the species
    • Family names always end in -aceae

    Phylogeny or Systematics

    • Shows evolutionary relationships and history among organisms
    • Some obtained from fossil record, most bacteria use rRNA sequencing or some other sequence information
    • Goal is to identify all organisms by 2025

    Phage Typing

    • Determines susceptibility to certain phage or bacterial viruses

    Genetics

    • DNA base composition: Guanine + cytosine moles% (GC)
    • DNA fingerprinting
    • Electrophoresis of restriction enzyme Digests
    • rRNA sequencing
    • Polymerase Chain Reaction (PCR)

    The 3 Domains

    • Eukarya: plants, animals, fungi, and protists
    • Bacteria (with peptidoglycan)
    • Archaea: with unusual cell walls and membranes

    Chemotaxonomy

    • Study of the chemical variation in microbial cells and the use of chemical characteristics in the classification and identification of bacteria
    • Examines the distribution of chemical macromolecules containing amino acids, peptides, lipids, polysaccharides, and other related polymers, proteins, enzymes, and other complex polymeric molecules
    • Characters used in bacterial chemotaxonomy:
      • Peptidoglycan
      • Diamino acids
      • Polysaccharides
      • Teichoic acids
      • Mycolic acids
      • Fatty acids
      • Polar acids
      • Isoprenoid quinones
      • Polyamines
      • Prokaryotic pigments
      • LPS

    Phylogeny

    • Evolutionary history of a group of organisms
    • Inferred indirectly from nucleotide sequence data
    • Molecular clocks: small subunit ribosomal RNA (SSU rRNA) genes
    • 16S rRNA in prokaryotes and 18S rRNA in eukaryotes

    Bacterial Phylogeny

    • Domain Bacteria: contains at least 80 major evolutionary groups (phyla)
    • Many groups are phenotypically diverse, i.e., physiology and phylogeny not necessarily linked

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    Description

    This quiz covers the basics of microbiology, including the definition, importance, and types of microorganisms, as well as the history of microbiology and the first microscope.

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