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History of Microbiology

Jun 5, 2025

Overview

This lecture reviews the history of microbiology, focusing on key figures, their contributions, and foundational concepts students need to know for exams.

Key Historical Figures in Microbiology

  • Robert Hooke first observed larger cells using a microscope and coined the term "cell," beginning cell theory.
  • Antonie van Leeuwenhoek developed a stronger microscope lens, observed live microorganisms, and is called the father of microbiology.
  • Francesco Redi challenged the spontaneous generation theory by showing maggots only appear when flies have access to meat.
  • Louis Pasteur disproved spontaneous generation, provided evidence for biogenesis, discovered fermentation, developed pasteurization, and supported the germ theory of disease.
  • Edward Jenner founded vaccination by showing cowpox exposure provided immunity to smallpox.
  • Joseph Lister applied germ theory to surgery, introduced handwashing and phenol for antiseptic surgery, and decreased surgical infections.
  • Robert Koch identified disease-causing bacteria, developed pure culture techniques, and established Koch’s postulates for linking microbes to diseases.
  • Alexander Fleming discovered penicillin, the first natural antibiotic.

Important Concepts and Theories

  • Cell theory: All living things are made of cells.
  • Spontaneous generation: Old belief that life arises from non-living matter.
  • Biogenesis: Principle that living cells arise only from preexisting cells.
  • Germ theory of disease: Diseases are caused by microorganisms.
  • Pasteurization: Heating liquids to kill microbes and prevent spoilage.
  • Vaccination: Using weakened microbes to provide immunity.

Koch’s Postulates

  • Pathogen must be present in all diseased and absent in healthy organisms.
  • Pathogen must be isolated and grown in pure culture.
  • Healthy individuals infected with the pathogen must develop the disease.
  • Pathogen must be re-isolated from the newly diseased host.

Key Terms & Definitions

  • Cell — The basic unit of life, as defined by cell theory.
  • Spontaneous Generation — Theory that life arises from non-living matter.
  • Biogenesis — Concept that life comes only from preexisting life.
  • Pasteurization — Process of heating to kill spoilage microbes.
  • Vaccination — Administration of a harmless microbe to provoke immunity.
  • Antiseptic Surgery — Surgical techniques using chemicals to prevent infection.
  • Pure Culture — A lab method to grow a single species of microbe.

Action Items / Next Steps

  • Review lecture notes and microbiology flashcards, focusing on bold, red text.
  • Study Koch’s postulates and the main contributions of each scientist discussed.