Bacteriology exam prep 1-3
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Questions and Answers

What is a common characteristic of microorganisms?

  • They exist as single cells or multiple cells (correct)
  • They can only be observed through a telescope
  • They are only found in humans
  • They are always visible to the naked eye

    • Who is credited with developing the first vaccine against smallpox?

  • Antonie van Leeuwenhoek
  • Edward Jenner (correct)
  • Robert Hooke
  • Louis Pasteur

    • What was the significance of Louis Pasteur's discovery of pasteurization?

  • It led to the development of vaccines
  • It solved the problem of spoilage during fermentation (correct)
  • It disproved the doctrine of spontaneous generation
  • It introduced the concept of microorganisms

    • What is the primary function of taxonomy in microbiology?

    <p>To classify bacteria into hierarchical units termed taxa</p> Signup and view all the answers

    What is the term used to describe the relationship between bacteria and their human hosts when bacteria help to digest food and produce energy?

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

    Who is known for being the first to document microscopic observations of muscle fibers and bacteria?

    <p>Antonie van Leeuwenhoek</p> Signup and view all the answers

    What is the term for the study of microorganisms?

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

    What is the purpose of a smear in microbiology?

    <p>To fix and stain a sample of bacteria for microscopical observation</p> Signup and view all the answers

    What is the main instrument used to take a small sample of a bacterial colony?

    <p>Inoculation loop</p> Signup and view all the answers

    What is the term used to describe the science of orderly classification of organisms into hierarchical units?

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

    What is the function of ribosomes in bacteria?

    <p>To synthesize proteins</p> Signup and view all the answers

    What is the main difference between Gram-positive and Gram-negative bacteria in the Gram staining technique?

    <p>The thickness of the peptidoglycan layer</p> Signup and view all the answers

    What is the purpose of the biofilm in bacteria?

    <p>To provide a common extracellular matrix for bacteria to attach to</p> Signup and view all the answers

    What is the mechanism by which energy is captured in the cell during oxidation and reduction reactions?

    <p>The production of ATP from ADP by adding a phosphate group</p> Signup and view all the answers

    What is the primary function of fimbriae and pili in bacteria?

    <p>To facilitate the attachment to host cells</p> Signup and view all the answers

    What is the primary mechanism of energy production used by bacteria that can oxidize glucose to CO2 and H2O?

    <p>Aerobic respiration</p> Signup and view all the answers

    What is the term used to describe the time required for one bacterial cell to divide into two cells?

    <p>Generation time</p> Signup and view all the answers

    What is the term used to describe bacteria that can grow in the presence of oxygen and also without oxygen?

    <p>Facultative aerobes</p> Signup and view all the answers

    What is the term used to describe bacteria that require elevated levels of CO2 for normal biosynthetic reactions?

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

    What is the term used to describe the minimal amount of organic compounds required by some bacteria for growth?

    <p>Growth factors</p> Signup and view all the answers

    What is the primary reason why mycobacteria are acid-fast?

    <p>Their cell walls have a high mycolic acid content</p> Signup and view all the answers

    In the Ziehl-Neelsen staining method, what is the purpose of the 3% HCl-ethanol solution?

    <p>To decolorize everything except the mycobacteria</p> Signup and view all the answers

    What is the purpose of the heat in the Schaeffer-Fulton staining method?

    <p>To allow the malachite green to penetrate the cell walls of endospores</p> Signup and view all the answers

    What is a characteristic of the bacterial capsule?

    <p>It is non-ionic in nature</p> Signup and view all the answers

    Why is malachite green used in the Schaeffer-Fulton staining method?

    <p>Because it can penetrate the cell walls of endospores</p> Signup and view all the answers

    What characteristic is unique to the cell walls of gram-positive bacteria?

    <p>Contains a thick peptidoglycan layer</p> Signup and view all the answers

    Which bacterial genus does not have a cell wall?

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

    What structure in gram-negative bacteria contains endotoxins?

    <p>Outer membrane</p> Signup and view all the answers

    Which arrangement describes a group of eight spherical bacteria forming a cube?

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

    What type of molecules are found in bacterial cytoplasm that assist in giving selective advantages such as antimicrobial resistance?

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

    Who was responsible for the invention of the Chamberland filter?

    <p>Charles Chamberland</p> Signup and view all the answers

    Which scientist discovered tuberculin simultaneously with Kristaps Helmanis?

    <p>Robert Koch</p> Signup and view all the answers

    Which disease did Adolf Mayer show to be infectious in 1876?

    <p>Tobacco mosaic disease</p> Signup and view all the answers

    Who was the first to use an oil immersion lens and condenser in microbiology?

    <p>Robert Koch</p> Signup and view all the answers

    What major role did Augusts Kirheršteins take on after the occupation of Latvia in 1940?

    <p>Head of the new Soviet government in Latvia</p> Signup and view all the answers

    What is the role of 20% copper sulfate solution in Anthony’s staining method?

    <p>To decolorize and counterstain the capsule</p> Signup and view all the answers

    Why is heat-fixation skipped in the capsule staining method?

    <p>Heat shrinks the organism and may create artifacts</p> Signup and view all the answers

    Which of the following is not a purpose of cultivating bacteria in a laboratory setting?

    <p>Modifying the genetic makeup of bacteria</p> Signup and view all the answers

    What substance is commonly used as a gelling compound in bacterial culture media?

    <p>Agar-agar</p> Signup and view all the answers

    Why should distilled water not be used to rinse the slide in Anthony’s staining method?

    <p>It can dissolve the capsules</p> Signup and view all the answers

    Study Notes

    History of Microbiology

    • Microbiology is the study of microorganisms, including bacteria, fungi, algae, protozoa, and viruses
    • Antonie van Leeuwenhoek (1632-1723) is considered the "father of microbiology" and was the first to document microscopic observations of microorganisms
    • Robert Hooke (1635-1703) was an English polymath who discovered the law of elasticity and was one of the first to discover microorganisms using a microscope
    • Edward Jenner (1749-1823) pioneered the concept of vaccines and developed the first vaccine against smallpox
    • Louis Pasteur (1822-1895) was a French chemist and microbiologist who developed the principles of vaccination, microbial fermentation, and pasteurization
    • Robert Koch (1843-1910) was a German physician and microbiologist who discovered the causative agents of tuberculosis, cholera, and anthrax

    Notable Latvian Scientists in Microbiology

    • Kristaps Helmanis (1848-1892) discovered tuberculin simultaneously with Robert Koch
    • Oto Kalniņš (1856-1891) discovered mallein together with Kristaps Helmanis
    • Augusts Kirhenšteins (1872-1963) was a Latvian microbiologist, politician, and educator who contributed to the development of science in Latvia, especially in microbiology, immunology, dairy farming, and biotechnology

    Bacteriology

    • Bacteriology is the study of the morphology, ecology, genetics, and biochemistry of bacteria
    • General characteristics of bacteria:
      • Ubiquitous in nature
      • Single-celled microscopic organisms
      • Can be harmful or beneficial to the host
    • Classification of bacteria involves taxonomy, identification, and nomenclature
    • Growth properties of bacteria include growth on media, motility, aerobic/anaerobic growth, and temperature tolerance

    Bacterial Anatomy and Physiology

    • Bacterial cell size ranges from 0.2-2 μm in diameter and 2-8 μm in length
    • Basic shapes of bacteria include spherical, rod-shaped, and spiral
    • Typical arrangements of bacteria include tetrads, diplococci, and streptobacilli
    • Structures of bacterial cell include cell envelope, cytoplasmic membrane, cell wall, and cytoplasm
    • Cell walls of gram-positive bacteria have a thick peptidoglycan layer, while gram-negative bacteria have a thin peptidoglycan layer and an outer membrane
    • Cytoplasmic structures include nucleoid, ribosomes, inclusions, plasmids, and spores
    • Surface structures include capsule, slime layer, flagella, and fimbriae/pili

    Gram Staining Method

    • The Gram staining technique is used to categorize bacteria into gram-positive or gram-negative
    • The stain allows determination of cell morphology and shape
    • Gram-positive bacteria have a thick peptidoglycan layer, while gram-negative bacteria have a thin peptidoglycan layer and an outer membrane

    Bacterial Physiology, Metabolism, Growth, and Nutrition

    • Metabolism involves energy production mechanisms, including fermentation and respiration

    • Bacterial growth involves an increase in the number of cells, not in their size

    • The growth curve includes lag phase, logarithmic phase, stationary phase, and death phase

    • Bacterial nutrition requires oxygen, carbon dioxide, temperature, pH, nutrients, and growth factors### Anaerobes

    • Anaerobes are categorized into two types based on their oxygen tolerance:

      • Aerotolerant anaerobes: do not grow in the presence of oxygen but survive exposure to oxygen for a short period (minutes to hours)
      • Obligate anaerobes: inhibited or killed by exposure to oxygen

    Environmental Requirements

    • CO2: required for normal biosynthetic reactions; some bacteria require elevated levels (capnophiles)
    • pH: most pathogenic bacteria grow best at a neutral pH (range 6.8-7.2)
    • Temperature: bacteria are categorized into three groups based on their optimal temperature for growth:
      • Psychrophiles: grow best at 10-15°C (range 0-25°C)
      • Mesophiles: grow best at 30-37°C (range 15-45°C)
      • Thermophiles: grow best at 55°C (range 35-70°C)
    • Ionic strength/osmotic pressure: most pathogenic bacteria grow best at osmotic pressures equivalent to physiological saline, but some can tolerate or grow at high salt concentrations

    Nutrients for Growth

    • Macronutrients: C, N, P, S, K, O, H (constitute 95% of dry cell weight)
    • Micronutrients: Cu, Fe, Mn, Mo, Zn, Ni (required for enzymes, cofactors, and vitamins)
    • Growth factors: specific vitamins, amino acids, purines, and pyrimidines required in small amounts by some bacteria

    Staining of Bacteria

    • Ziehl-Neelsen method: used to stain acid-fast bacteria (e.g., Mycobacterium)
    • Schaeffer-Fulton method: used to stain endospores (e.g., Bacillus spp. and Clostridium spp.)
    • Anthony's method: used to stain capsules (the polysaccharide, mucus-like layer around bacterial cells)
    • Staining process: heat-fixation, primary stain, decolorizing agent, and counterstain are used to differentiate bacteria

    Cultivation of Bacteria

    • Cultivation: the process of propagating organisms by providing proper environmental conditions
    • Requirements for growth: nutrients, pH, temperature, aeration, salt concentration, and ionic strength
    • Media: a specifically prepared environment in the laboratory that ensures the preservation, growth, and reproduction of bacteria
    • Media composition: nutrients, energy source, essential metals and minerals, buffering agents, indicators, selective agents, and gelling compound (agar-agar)
    • Classification of media: based on composition, consistency, and purpose

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    Description

    History; Bacterial anatomy: structures and functions; forms and arrangements;Bacterial physiology, metabolism, growth and nutrition; gram staining, Ziehl-Neelsen method, Schaeffer-Fulton method, Anthony’s method

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