Exam review

Chapter 1 - Invisible World

What is Microbiology?

  • Study of organisms that cannot be seen by the naked eye.

1. The History of Microbiology

  • Spontaneous Generation

    • Hypothesis: Living organisms arise from nonliving matter; a "vital force" forms life.

  • Biogenesis

    • Hypothesis: Living organisms arise from preexisting life.

  • Key Experiments

    • Francesco Redi

      • Tested spontaneous generation with jars and maggots, concluded it did not occur.

    • John Needham

      • Suggested spontaneous generation occurred via broth in flask experiment.

    • Lazzaro Spallanzani

      • Refuted Needham; claimed microbes were introduced from open air.

    • Louis Pasteur

      • Disproved spontaneous generation, proved theory of biogenesis with his "swan-neck" flask experiments.

2. Contributions of Early Microbiologists

  • John Tyndall (1820-1893)

    • Discovered the bacterial structure, endospore.

  • Joseph Lister (1827-1912)

    • Father of antiseptic surgery.

  • Edward Jenner (1749-1823)

    • Developed vaccination technique; first to prevent smallpox.

  • Fanne Eilshemius Hesse (1850 - 1934)

    • Proposed the use of agar in culture media.

  • Richard Petri (1887)

    • Developed the Petri dish for culture media.

  • Alexander Fleming (1881-1955)

    • Discovered penicillin, effective against several pathogenic bacteria.

  • Paul Ehrlich (1845-1915)

    • Developed the treatment of syphilis using arsenic.

  • Antonie Van Leeuwenhoek

    • First to observe bacteria and protists.

  • Louis Pasteur

    • Demonstrated fermentation by microorganisms and invented pasteurization.

  • Robert Koch

    • Discovered bacteria causing anthrax, cholera, and tuberculosis.

  • Robert Hooke

    • Marked the beginning of cell theory.

Germ Theory & Koch's Postulates

  • Germ Theory

    • Robert Koch confirmed that many diseases are caused by microbes.

  • Koch's Postulates

    1. The suspected pathogen must be found in all cases of the disease, absent in healthy individuals.

    2. The suspected pathogen can be isolated and grown in pure culture.

    3. A healthy host infected must exhibit the same disease symptoms as the original.

    4. The pathogen must be re-isolated from the new host, identical to the original.

3. Taxonomy Basics

  • Taxonomy

    • System of organizing, classifying, and naming organisms, developed by Carolus Linnaeus.

  • Phylogenies

    • Evolutionary history of organisms.

  • Ernst Haeckel

    • Proposed the kingdom Protista for unicellular organisms; a fourth kingdom, Monera, for unicellular organisms without membrane-bound nuclei.

  • Robert Whittaker

    • Proposed the kingdom Fungi and added categories above kingdoms (e.g., Empires Prokaryota and Eukaryota).

  • Binomial Nomenclature

    • Genus + species (italicized or underlined, with Genus capitalized).

  • Bergey's Manual

    • Reference for identifying and classifying prokaryotes using biochemical tests and genetic sequencing techniques.

4. Three Domain Classification

  • Domains: Bacteria, Archaea, Eukarya.

5. Approaches to Classifying Organisms

  • Two-Kingdom System (Linnaeus): Plantae & Animalia.

  • Five-Kingdom System (Whittaker): Monera, Protista, Fungi, Plantae, Animalia.

  • Six-Kingdom System (Woese): Bacteria, Archaea, Protista, Fungi, Plantae, Animalia.

  • Three Domain System (Woese): Bacteria, Archaea, Eukarya.

6. Levels of Classification

  1. Domain (Eukarya - Eukaryotes)

  2. Kingdom (Animalia - multicellular & heterotrophs)

  3. Phylum/Division (Chordata - animals with a backbone)

  4. Class (Mammalia - have sweat glands & produce milk)

  5. Order (Carnivora - meat-eating animals)

  6. Family (Canidae - wolves, foxes)

  7. Genus (Canis - dogs & wolves)

  8. Species (Canis lupus familiaris - domesticated dog)

7. Microbial Diversity & Structure

  • Prokaryotes

    • Cells lack a nucleus, most have cell walls containing peptidoglycan.

    • Described by shape: round (coccus), rod (bacillus), spiral (spirillum).

    • Some are photosynthetic, others obtain energy from environmental compounds.

  • Archaea

    • Walls do not contain peptidoglycan, contain pseudopeptidoglycan.

  • Eukaryotes

    • Cells contain a nucleus, include protists, fungi, and helminths.

8. Microbiology as a Field of Study

  • Bacteriology: Study of bacteria.

  • Mycology: Study of fungi.

  • Protozoology: Study of protozoa.

  • Parasitology: Study of helminths and other parasites.

  • Virology: Study of viruses.

  • Immunology: Study of the immune system.