AP Biology

CELL LAB

This was one of my favorite labs we conducted. It involved using an online database of DNA sequences from a verity of species and a powerful tool that compared and contrasted a given sequence to this database. It gives you lots of information, one of which includes the similarity between the given sequence and the one of another species. We used this to learn more about evolution. I really enjoyed how hands-on and relevant this was! I was impressed that we got to work with real data. Here are the questions, and my lab report:

Analyzing Results:

• What species in the BLAST results has the most similar gene sequence to the gene of interest?
• Where is that species located on your cladogram?
• How similar is that gene sequence?
• What species has the next most similar gene sequence to the gene of interest?
• Based on what you have learned from the sequence analysis and what you know from the structure, decide where the new fossil species belongs on the cladogram with the other organisms. Redrawn the cladogram.
• On the main page of BLAST, click on the link "List all Genomic Databases." How many genomes are currently available for making comparisons using BLAST? How does this limitation impact the proper analysis of the gene data used in this lab?
• What other data could be collected from the fossil specimen to properly identify its evolutionary history?

Designing and Conducting your Investigation:

• What gene did you investigate?
• What is the function in humans of the protein produced from that gene?
• Would you expect to find the same protein in other organisms? If so, for what function/benefit?
• Is it possible to find the same gene in two different kinds of organisms but not find that protein that is produced from that gene?
• If you found the same gene in all organisms you test, what does this suggest about the evolution of this gene in the history of life on earth?
• Does the use of DNA sequences in the study of evolutionary relationships means that other characteristics are unimportant in such studies?

In this lab, we used what we learned about genes and biotechnology to conduct an experiment on bacterial transformation. The goal was for an e.coli colony to uptake a pGLO gene plasmid, which transcribes for a glowing effect under a UV lamp, present in some species of jellyfish. During the first part of the lab, we actually prepared the DNA samples ourselves. Prior to that we prepared and grew e.coli colonies in petri dishes. A few days later, we prepared the samples by mixing the pGLO DNA, enzymes, and transformation solutions while paying close attention to the instructions. Sometimes the samples had to be chilled, or heated at exactly 40°C for exactly fifty seconds, or shaken before adding the e.coli we'd grown. We compared e.coli colonies that contained the pGLO gene, that didn't contain the pGLO gene, that contained ampicillin (which hampers the growth of bacteria) and arabinose (used as a source of energy and carbon). The e.coli colonies that were mixed with the pGLO gene and contained arabinose had successfully transformed and had absorbed the pGLO plasmid. This caused the e.coli to glow under UV light, which can be seen above. The 76 page lab can be viewed below (the procedure begins at page 37)