BIO 300 Lecture Notes - Lecture 3: Mitochondrion, Symbiogenesis, Microbiological Culture
6 Sep 2016
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Louis pasteur: considered father of modern microbiology, demonstrated air is filled with microorganisms, was asked to figure out how to separately produce alcohol, and not produce vinegar. Vats inoculated w/ vasilis --> vinegar: filtered air through cotton plug. Many looked identical to those found in broths: swan neck flask experiment. Air escapes from open end of flask when swan neck flask is boiled. Microorganisms from air settle in the bend. Flask tilted so that sterile broth comes in contact w/ microorganisms from air. The flask is both the control and the changing variable: pasteurization: does not fully sterilize, keeps temperature at a constant so that # of organisms alive are kept in low numbers. Pasteur"s results not fully reproducible --> some scientists remained skeptical. John tyndall finally explained conflicting data: proved pasteur correct, sterilizing broth required different times. Some sterilized in 5 mins, others more than 5 hours. 1876 ferdinand cohn discovered endospores: heat resistant form of bacteria.
