Lab Report 6 Molecular Biology

Lab Report 6 Molecular Biology - Bacterial Transformation...

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Bacterial Transformation of Escherichia coli and Ampicillin Resistance Edna Batayola Abstract: The best-studied bacterium is Escherichia coli, “the laboratory rat of molecular biology. E. coli reproduce very rapidly; a single microscopic cell can divide to form a visible colony with millions of cells overnight. Some plasmids have the amp R gene, which confers resistance to the antibiotic ampicillin. E. coli cells containing this plasmid, termed "+amp R " cells, can survive and produce colonies. Cells lacking the amp R plasmid, termed "–amp R " cells, are sensitive to the antibiotic, which kills them. E. coli cells can only show growth on an ampicillin plate if they are transformed. In experimental tube #1, +amp R cells and had no ampicillin in the growth medium showed growth. Experimental tube #2, +amp R cells and contained ampicillin in the growth medium, showed no growth.
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Introduction The purpose of this lab was to use antibiotic resistant plasmids to transform Escherichia coli; this was completed by transforming bacterial cells through insertion of an ampicillin- resistant gene into the E.coli cells. E. coli is the most common bacterium in the human gut. E. coli reproduces very quickly. For example, overnight, a colony of a million E. coli cells can be produced. Like all bacterium, E. coli has no nuclear envelope that covers the bacterial chromosome; therefore, there is no true nucleus. E. coli cells containing this plasmid, termed "+amp R " cells, can survive and produce colonies. Cells lacking the amp R plasmid, termed "– amp R " cells, are sensitive to the antibiotic, which kills them. Plasmids are small DNA molecules that carry genes for specialized functions, including the resistance to drugs. They are circular pieces of DNA located outside the bacterial chromosome. In genetic engineering, plasmids are used to introduce foreign genes into a bacterial cell. Certain plasmids called R plasmids carry genes for resistance to antibiotics such as ampicillin. These plasmids have the ampR gene, which confers resistance to ampicillin. They also act as carriers (vectors) for introducing foreign DNA from other bacteria. In this experiment, the bacterial recombination of transformation is used by antibiotic resistance plasmids to transform E. coli. Transformation is the phenomenon defined as a change in genotype and phenotype due to the assimilation of foreign DNA by a cell. In 1928, Frederick Griffith discovered transformation by studying streptococcus pneumoniae, a bacterium that causes pneumonia in mammals. His experiment led to the discovery that DNA is the substance of
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Lab Report 6 Molecular Biology - Bacterial Transformation...

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