THE MOLECULAR BASIS OF INHERITANCE
RECOMBINANT DNA
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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selects for plasmids containing particular DNA fragments.
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select for bacteria containing plasmids
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selects for bacteria lacking plasmids.
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prevents contamination of the medium
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Detailed explanation-1: -Antibiotics commonly used for plasmid selection These antibiotic resistance genes not only give the scientist with an easy way to detect plasmid-containing bacteria, but also provide those bacteria with a pressure to maintain and replicate your plasmid over multiple generations.
Detailed explanation-2: -The presence of an antibiotic resistance gene on a plasmids allows researchers to easily isolate bacteria containing that plasmid from bacteria that do not contain it by artificial selection (i.e. growing the bacteria in the presence of the antibiotic).
Detailed explanation-3: -Plasmids have been key to the development of molecular biotechnology. They act as delivery vehicles, or vectors, to introduce foreign DNA into bacteria. Using plasmids for DNA delivery began in the 1970s when DNA from other organisms was first ‘cut and pasted’ into specific sites within the plasmid DNA.
Detailed explanation-4: -The bacteria are given a heat shock, which “encourages” them to take up a plasmid. Most bacteria do not take up a plasmid, but some do. Plasmids used in cloning contain an antibiotic resistance gene. Thus, all of the bacteria are placed on an antibiotic plate to select for ones that took up a plasmid.