Microbiology Quiz 1 - Chapter 1

Microorganisms and Microbes

• Microorganisms are organisms too small to be seen without a microscope.
• Types of microbes include bacteria, fungi, protozoa, and viruses.
• Pathogenic microorganisms break down organic waste, generate oxygen, and can produce substances like ethanol and acetone.

Importance of Microbiology

• Understanding microorganisms helps prevent food spoilage, diseases, and informs about their causes and transmission.
• Carolus Linnaeus established scientific nomenclature in 1735, introducing the system of assigning two names to each organism: genus and specific epithet.

Scientific Naming Conventions

• Scientific names are always italicized or underlined.
• The genus name is always capitalized; the specific epithet is always lowercase.

Notable Microorganisms

• Escherichia coli, discovered by Theodor Escherich, is commonly found in the intestines.
• Staphylococcus aureus refers to spherical "coccus" shaped cells clustered like "staphylo."

Bacteria and Prokaryotes

• Bacteria are prokaryotic, single-celled organisms that reproduce by binary fission.
• Prokaryotes derive nutrition from organic/inorganic chemicals or through photosynthesis.

Archaea

• Archaea are prokaryotic organisms that lack peptidoglycan in their cell walls and thrive in extreme environments.
• Types of archaea include:
  • Methanogens that produce methane.
  • Extreme halophiles that live in high salt concentrations.
  • Thermophiles that thrive in high-temperature environments.

Fungi and Eukaryotes

• Fungi are eukaryotes with chitin cell walls and obtain energy by absorbing organic chemicals.
• Yeasts are unicellular, while molds and mushrooms are multicellular.

Other Eukaryotic Microorganisms

• Protozoa are eukaryotes that absorb or ingest organic chemicals, existing freely or as parasites.
• Algae are photosynthetic eukaryotes with cellulose cell walls, found in various water bodies.

Viruses

• Viruses are acellular entities made up of either DNA or RNA, encased in a protein coat.

Classification of Microorganisms

• Microorganisms are classified into three domains based on cellular organization: Bacteria, Archaea, and Eukarya.

Historical Contributions to Microbiology

• In 1665, Robert Hooke implicated all living things are made of cells, laying the groundwork for cell theory.
• Anton van Leeuwenhoek first observed microbes (animalcules) between 1623-1673.
• Theories: Spontaneous generation suggests life arises from non-living matter, while biogenesis states living cells only come from existing living cells.

Key Experiments in Microbiology

• Francesco Redi demonstrated that decaying meat in jars did not produce maggots.
• John Needham boiled nutrient broth and let it cool in a covered flask; microorganisms still appeared.
• Lazzaro Spallanzani boiled nutrient solutions in sealed flasks to prevent growth of microbes.
• Louis Pasteur presented evidence that microorganisms are present in the air, disproving spontaneous generation.

The Golden Age of Microbiology

• The period between 1857-1914 is marked as the Golden Age, beginning with Pasteur's pivotal experiments.

Discoveries and Innovations

• Robert Koch developed experimental steps for understanding disease causation.
• Chemo-therapeutics and antibiotics emerged, with Paul Ehrlich developing salvarsan for syphilis in 1910 and Alexander Fleming discovering penicillin in 1928.

Fields of Study in Microbiology

• Mycology: Study of fungi.
• Bacteriology: Study of bacteria.
• Phycology: Study of algae.
• Microbial genetics: Study of hereditary traits in microbes.

Interesting Observations

• Microbial coloration can change, often from red to yellow.