18. Incubate the plates upside down at 37c for about 18 hours. DO NOT WAIT LONGE
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18. Incubate the plates upside down at 37c for about 18 hours. DO NOT WAIT LONGER THAN 18HOURS Answer the following questions before you leave Talk with the instructor to make sure your answers are comect. You will need to discuss ALL of these questions in your lab report. Plate Plate 2" Plate 3 Plate 4 1. Which plate should contain the most number of ells growing (assume that ne on is not 100% efficient Why? Platg 4 t beca it will conta n ame allow all 2. Which plate should contain the least number of cells growing? Why? Platu ,5 it contains antibio ampi illin 3, What do the plates 1.3, and 4 tell you (what is the purpose for each of these plates)? Give an explanation for each plate. For example, do you expect growth or no growth on each plate? If you observed the opposite of what you what does this mean? 4. Which plat will have green cells under a uv light? Why? 5. which it contains arab, has thu plates will have cells that NOT green under a uv light? Why? are Not contain 6. The ontain the pGlo DNA, so the cells w transformed with the plasmid. Why does it still have to go through the heat shock the same way as the (+DNA) tube (be specific)? Sa we can deterMINe thw p nor heat shock as rel 7. An organism's environment can determine its physical trait (phenotype). a) After transformation is successful, what two factors must be present in order for you to observe the green fluorescence of the transformed cells (other than the pGlo? Explain what each factor is doing to cause green fluorescence. 69Explanation / Answer
1.
Plate 4 will contain maximum number of growing cells because even though there is no plasmid, all the bacterial cells can grow well in the absence of an antibiotic.
2.
Plate 3 will contain least number of growing cells. This is because the bacteria are not transformed with DNA containing antibiotic but allowed them to grow in the presence of an antibiotic. The antibiotic in the media will kill untransformed cells.
3.
Plate 1: Effect of arabinose on pGLO expression
Plate 3: Competent cells used for transformation are not contaminated already with an antibiotic.
Plate 4: Competent cells used for transformation are fine that they can grow in the absence of an antibiotic.
4.
Plate 2 cells will show fluorescence under UV light as they can express GLO gene.
Plate contains antibiotic. So, only transformed cells will grow.
It also contains arabinose which induces pGLO expression.
5.
Plate 3 and 4 contains cells that are not transformed with pGLO gene. So, they do not produce Fluorescence.
6.
All the controls must be treated the same way as the test in order to make sure that the experimental conditions are not detrimental or inducible for the test.
So, even though tubes do not contain DNA, heat shock will tell that cells can survive the heat shock.
7.
a.
1. Arabinose: Induces pGLO expression
2. UV: Excites GLO protein to cause fluorescence
b.
It is not energy efficient for the cell to synthesize all the genes all the time. It would be wasteful to synthesize a protein that it is not going to use.
So, housekeeping genes are always expressed as they are required for regular metabolism.
Specific gene expression is induced only when they are required.
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