METHODS OF CLASSIFYING AND IDENTIFYING MICROORGANISM1

METHODS OF CLASSIFYING AND IDENTIFYING MICROORGANISM1 -...

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METHODS OF CLASSIFYING AND IDENTIFYING  MICROORGANISMS FATTY ACID PROFILES-- often the type and amount of various fatty acids are characteristic  of certain species of bacteria. Cellular fatty acids can be separated and compared to known  profiles.  FLOW CYTOMETRY-- fluid containing bacteria is forced through a small opening. Using a  laser, the size, shape, and surface characteristics can be identified. This can make a tentative  identification without waiting for a culture. DNA BASE COMPOSITION--t he DNA of an organism can be analyzed and the percentage of  guanine + cytosine can be compared to the percentage of adenine + thymine. The (G + C)  percentage will be very close to the same in closely related organisms and differ more in  organisms that are not so closely related. Similar percentages are not conclusive proof of a  relationship, but they do give a good indication of whether more tests should be done. This test is 
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Unformatted text preview: often used because it is relatively simple and inexpensive. DNA FINGERPRINTING —this is a more complicated test. It is time-consuming and expensive. However, it actually determines the sequence of bases in an organism's DNA and can give much more conclusive proof of relatedness. Restriction enzymes cut a molecule of DNA everywhere a specific base sequence occurs. One specific restriction enzyme would cut DNA everywhere these sequences occur: G ↓ A A T T C or C T T A A G DNA samples from two different organisms are treated separately with the same restriction enzyme. The resulting fragments are separated by electrophoresis, and the number and sizes of the fragments are compared. The more similar the patterns, the more closely related the organisms....
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This note was uploaded on 01/23/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.

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