Microbiology Test 1- Short Answer
A contaminated food sample contains several different species of bacteria. A food microbiologist is interested in studying just one of these species. Describe the sequence of procedures that the microbiologist must perform in order to obtain a pure culture in different serial dilutions of the bacterial species of interest from this food sample. Detail all the necessary media and equipment.
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Flagellum
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Reducing Medium
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Synthetic and non-synthetic medium
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What is the main purpose of Gram staining? Explain how the results of gram staining be interpreted?
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Write the difference between differential media and differential staining.
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Write the major structural differences between Gram positive and negative bacteria
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Explain the formation of an endospore in a bacterial cell.
Endospores are heat resistant bacteria. They were discovered by Tyndall & Cohn
What are the contributions of Robert Koch to the field of microbiology? Explain.
Kock verified the germ theory, made a pure culture, and discovered the cause of TB and Anthrax
Classify bacteria based on the number and position of flagella
Monotrichous- single flagellum at one end Lophotrichous- Small bundles emerging from the same site Amphitrichous- flagella at both ends of the cell Peritrichous- flagella dispersed over surface of the cell
Describe the experiment that Louis Pasteur did with swan-necked shaped tubes to disprove spontaneous generation.
Pasteur took two swan-necked flasks and broke one of them so that it's neck just extended down and the boiled the substance inside of them killing any bacteria that could have formed. The vapor caused water to become stuck in the unbroken flask which trapped the dust particles from contaminating the solution. However, dust particles entered the broke flask and soon microorganisms began to grow out of the solution. This experiment is important because it disproved the theory of spontaneous generation.
Write the major differences between prokaryotes and eukaryotes
Prokaryotes: Pre-nucleus, simple cells, unicellular, lack nuclei and membrane-bound organelles Eukaryotes: True nucleus, complex cells, unicellular & multi-cellular, contain a nucleus and membrane-bound organelles
