Biology Lab
IB SL Biology Lab
Molecular Biology:
Transformation and Electrophoresis
Christina Qi
2/16/07
Aim:
How can a plasmid be engineered to include a foreign piece of DNA and how does gel electrophoresis separate DNA molecules present in a mixture?
Hypothesis:
If the pGLO plasmid is inserted into competent Escherichia coli cells, then the transformed bacteria will be resistant to ampicillin and will glow green under UV light. If samples of DNA are cut using certain restriction enxymes and separated using gel electrophoresis, then the smaller the DNA fragment cut, the greater the distance it will travel in the gel.
Variables: The control plates used in transformation are the LB and second LB/Amp plates marked with a “-“. The control for restriction digest was the ladder. The independent variables are the different cultures of the E. coli, and the +LB/Amp and +LB/Amp/ara plates form the experiment group. The dependent variable is whether the cells glow green under the UV light and whether they are resistant to ampicillin or not. The variables in restriction digest are the other 4 samples. The dependent variable is the length that the DNA fragments travel while the independent variable is the size of the DNA fragments.
Method for Controlling Variables: The variables were kept controlled by using different inoculating loops to add and spread out each solution. This was done to prevent any solutions from mixing together. The same amount of pGLO plasmid solution was added by dipping the loop until a bubble was formed across the loop opening. The tubes were incubated for the same amount of time and heat shocked for the same amount of time. The same amounts of Luria broth and cell suspension were used to keep the number of individual colonies controlled.
Materials Used: For Transformation: 2 culture tubes (one marked “+” and one marked “-“) 4 sterile transfer pipettes 1 incubator (37° C) 4 LB plates (LB, 2 LB/Amp,
Molecular Biology:
Transformation and Electrophoresis
Christina Qi
2/16/07
Aim:
How can a plasmid be engineered to include a foreign piece of DNA and how does gel electrophoresis separate DNA molecules present in a mixture?
Hypothesis:
If the pGLO plasmid is inserted into competent Escherichia coli cells, then the transformed bacteria will be resistant to ampicillin and will glow green under UV light. If samples of DNA are cut using certain restriction enxymes and separated using gel electrophoresis, then the smaller the DNA fragment cut, the greater the distance it will travel in the gel.
Variables: The control plates used in transformation are the LB and second LB/Amp plates marked with a “-“. The control for restriction digest was the ladder. The independent variables are the different cultures of the E. coli, and the +LB/Amp and +LB/Amp/ara plates form the experiment group. The dependent variable is whether the cells glow green under the UV light and whether they are resistant to ampicillin or not. The variables in restriction digest are the other 4 samples. The dependent variable is the length that the DNA fragments travel while the independent variable is the size of the DNA fragments.
Method for Controlling Variables: The variables were kept controlled by using different inoculating loops to add and spread out each solution. This was done to prevent any solutions from mixing together. The same amount of pGLO plasmid solution was added by dipping the loop until a bubble was formed across the loop opening. The tubes were incubated for the same amount of time and heat shocked for the same amount of time. The same amounts of Luria broth and cell suspension were used to keep the number of individual colonies controlled.
Materials Used: For Transformation: 2 culture tubes (one marked “+” and one marked “-“) 4 sterile transfer pipettes 1 incubator (37° C) 4 LB plates (LB, 2 LB/Amp,