Monthly Archives: May 2012

pGLO transformation

The central dogma of biology is DNA->RNA->Protein->Trait.

DNA->RNA is a process called transcription. During transcription, DNA is read by an enzyme called RNA polymerase which produces a  complementary RNA strand, but instead of thymine pairing with adenine, RNA uses uracil to pair with adenine. Once transcription is complete, the RNA strand is sent out into the cytoplasm. The mRNA strand is sandwiched between two ribosomal units, which then two tRNA attach to. These tRNA take the codons from the mRNA and translate them into amino acids, which they link together, forming a long amino acid chain called a protein. This process is called translation because the tRNA is translating the from the language of DNA and RNA (nucleotides) to the language of protein (amino acids). Then the proteins make up the traits in your body because they are the structure of almost everything in your body.

In the pGLO transformation lab, we genetically modified e.coli bacterium. We did this by placing pGLO plasmids around the bacterium and then, using heat shock, we made them open their pores to take in the plasmids. The plasmids DNA made new proteins called GFPs, or Glowing Fluorescent Proteins. This gene was turned on by the presence of arabinose. So the DNA from the plasmids was transcripted to RNA and then Translated to the GFP Proteins which made the bacteria glow. On one plate we had just the unmodified bacteria and LB (a growth factor). On another plate we had the unmodified bacteria, LB, and ampicillin. On another plate we had modified bacterium, ampicillin and LB. And on the last plate we had LB, Ampicillin, Arabinose and modified bacteria. on plate 1 we had lots of growth, but no glowing. On plate 2 we had no growth because the ampicillin killed the bacteria. On plate 3 we had bacteria but no glowing ( the plasmid we put in made the bacteria resistant to ampicillin). And on plate 4 we had glowing growing bacteria. The arabinose on plate 4 turned on the gene  that made GFP, which is why it is the only plate that glowed.

 

here is a picture courtesy of https://andrewsbioblog.files.wordpress.com/2012/05/p-pglo-4plates-200.gif?w=231