Unformatted text preview: Introduction to the Microbial World
Part 1 of the Lecture
This will be an introduction to the field of microbiology. Part 2 of the Lecture
This is the part of the lecture that you will need to know for the exam: Pasteur’s experiment
disproving spontaneous generation and Koch’s postulates.
Textbook Reading Pages 39-45 Questions you should be able to answer after reading the text:
1. The observation was made, after food was left to stand for some
time, that there would be a large number of microbes associated with
it; whereas at the start, the food did not have a large number of
microbes associated with it. Why can this observation be equally
well explained by the theories of spontaneous generation of the
microbes as well as microbes arose from pre-existing microbes?
2. Be able to outline Pasteur’s swan-neck flask experiment according
the flow chart of the “Scientific Method” (see section below).
3. Did Pasteur’s experiment prove that spontaneous generation can
4. In Koch’s postulates, why is it important to show that the suspected
pathogen can be re-isolated from the diseased animal?
5. In Koch’s postulates, why might an inoculated animal show disease
and it not be possible to re-isolate the suspected pathogen? 1 Review of the Scientific Method Step 1: Observation
Step 2: Hypothesis/Model/Theory
Step 3: Design Experiment
Experimental Group Control Groups Repeat from Step 2
Scientific hypotheses yield testable predictions. The experiments designed to test the hypothesis
should yield one result (i.e. observation) if the hypothesis is correct and a different result if the
hypothesis is incorrect.
Control groups allow comparison between two samples that differ for a defined set of variables. 2 ...
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- Summer '10