Introduction to Microbiology

Overview

• Microbiology is the study of microorganisms, also called microbes.
• Microbes are ubiquitous, meaning they are found everywhere (e.g., ocean, Arctic, dirt, air, skin).
• Microorganisms are too small to be seen without a microscope.
• Not all microbes are harmful; many are beneficial (e.g., fermentation of food, oxygen production).

History of Microbiology

• Hippocrates: First to dismiss supernatural causes of disease, believed in natural causes.
• Van Leeuwenhoek: Father of Microbiology, developed the first microscope, discovered microbes in rainwater.
• Robert Hooke: Father of Cell Theory, discovered cells in cork, not specifically microbes.
• Louis Pasteur: Discovered fermentation and pasteurization, demonstrated microbes in the air causing spoilage.
  • Developed vaccines later in his research.
• Robert Koch: Developed Koch's postulates, demonstrated specific microbes can cause specific diseases.
  • Studied anthrax, isolated Bacillus anthracis.

Classification of Microorganisms

• Three main domains:
  1. Bacteria: Most microbes studied fall here.
  2. Archaea: Odd microbes, distinct from bacteria.
  3. Eukarya: Includes some microbes, plants, and animals.
• Naming microbes uses binomial nomenclature.
  • Genus is capitalized, species is not.
  • Names must be underlined or italicized.
  • Abbreviations use the first letter of the genus followed by the species name.

Sizes and Domains

• Microbes vary in size, viruses are smaller than bacteria.
• Eukarya: True membrane-bound organelles.
• Bacteria & Archaea: Prokaryotes, no membrane-bound organelles.
• Viruses: Not technically living, unique microbes.

Types of Microorganisms

• Algae:
  • Can be unicellular or multicellular.
  • Cell walls made of cellulose.
  • Photosynthetic, produce oxygen.
  • Found in everyday products (e.g., ice cream, toothpaste).
• Protozoa:
  • Unicellular or multicellular.
  • Highly motile, classified by movement organelles (cilia, flagella, pseudopods).
  • Can be parasitic or harmless.
• Fungi:
  • Include yeast and molds.
  • Cell walls made of chitin.
  • Mostly free-living and harmless, some are pathogenic.
• Helminths:
  • Parasitic worms, microscopic stage transmits between hosts.
• Viruses:
  • Acellular, obligate intracellular parasites.

Summary

• Chapter 1 provides an overview of different types of microbes.
• Focus on bacteria initially, then move to eukaryotic microbes.