Arabdiopsis Lab

John Arore

June 10, 2009

Bio 912

Arabdiopsis

3)

Plate # | Control(s) |

1 | no arabinose |

2 | no CaCl2, no arabinose |

3 | None |

4 | no CaCl2 |

5 | no pGLO, no arabinose |

6 | no ampicillin, no arabinose |

4) It is necessary to include these controls to understand the effects of CaCl2 on the transformation process, as well as the effects of the presence of arabinose, pGLO, and ampicillin on gene expression. For plates 2 and 4, we would expect to see no colony growth or glowing under the light because no CaCl2 was used to facilitate DNA uptake of the pGLO plasmid. Without the pGLO on plate 5, we would expect a similar result because there was no gene to express. Without arabinose on plate 1, we would expect colony growth with competent cells including the pGLO plasmid, but no glowing (no arabinose), and no bacteria “lawn” (the antibiotic ampicillin is present and it has a varying effect depending upon the amount of bacteria that is successfully transformed with the Ampr marker included. In any case, it would prevent a lawn from growing). On plate 6, without this antibiotic, growth of the bacteria would not be inhibited, and we would expect a lawn to form, which it did (there is no arabinose, so the cells did not glow). On plate 3, in which we had no controls, we were able to visualize the effects of transformation and expression and how no lawn formed because ampicillin was present.

In summation, we used controls to understand and visualize the effects of those substances facilitating DNA uptake and expression, as well as resistance, and observe what would happen when some of these were not included in the process. This was necessary to understand the transformation process and to test the permeability of bacterial cell wall membranes in competent cells.

4) On plate 1, we did not observe colony growth. However there should have been growth if we had successfully made competent bacteria cells using CaCl2 to accept the pGLO...