Unit 5 Reflection

In this unit, we learned about the central dogma. The central dogma says that information travels from the DNA to the RNA to the proteins, which make up the physical traits that we have. This process can be broken down even further into two steps: transcription and translation. Transcription is the process in which DNA unzips and RNA is made to match the spare nucleotides to make messenger RNA (mRNA). In translation, mRNA arrives at the ribosomes, where the codons are translated into a code for proteins, which are produced and make up our physical traits. There are also mutations and different things that can regulate gene expression, but those are rather slightly less relevant to the central idea of the unit.

One of my main strengths in this unit was that I was able to easily translate and transcribe different DNA pairing, RNA sequences, and going from codon to protein, This made the protein synthesis lab quite easy for me, as I was done in less than 10 minutes. However, one of my weaknesses was not being able to visualize things. When Mr. Orre called on students to walk up to the board to label the different items related to regulating gene expression, I was not even able to identify a single one. Thank goodness I wasn't called up!

Yet still, I have many questions. Mr. Orre said that this unit would bridge the gap between how our chromosomes affected our traits, but I still don't quite get how different alleles correspond to different base pair codes and how the types of proteins can create so many different combinations that affect our physical traits.

As a student, I feel like I have definitely grown after this unit. DNA had always been one of the most puzzling concepts for me that I couldn't quite grasp. However, I feel that after this unit, especially after creating the DNA model, my understanding of the structure and function of DNA has definitely expanded. Also, my learning skills have definitely improved. I used to rush through my vodcasts with haste, focusing more on completing the task rather than actually trying to learn more as a biology student. Now, I listen carefully and try to pick up on as much detail as possible, even referencing the textbook when the vodcast is unclear. I feel like this time, unlike the others, I will not be cram-studying the night before the test because I think I already have ample knowledge to do well on the final. I might study a little bit here and there and review my peer study guides, but I will definitely be getting a good night's sleep this time.   

Protein Synthesis Lab

In this lab, we asked the question: "how does the body produce proteins?" In the process of protein synthesis, RNA polymerase reads the DNA and transcribes it into a code for the messenger RNA (mRNA). Then, the RNA travels to the ribosomes. They bond, and the mRNA is read, each codon representing a specific protein. Finally, the protein is made based on the code read from the mRNA.

Frameshift mutation seemed to have the greatest effect on the proteins, and yes, it does matter where the mutation because an insertion or deletion near the beginning of the sequence can offset the entire rest of it, but one of these at the end might not do much. If the T was at the end, it would not have affected the sequence before it. However, in some cases, substitution can cause a huge change in protein as well.

In step 7, the mutation I chose was a simple substitution on the 6th base. A substitution at the end of a codon may seem like nothing at first, but the change was actually pretty massive. This simple substitution caused the second codon to go from a Tyr protein to a Stop protein. So effectively, the new sequence literally became just start-stop. Quite a difference with such a small substitution. And yes, of course, like always, the spot where the mutation occurs definitely matters when choosing the mutation that will create the biggest or smallest change.

Mutations can affect our lives because if a section of our DNA is deleted, inserted, or substituted for, it could cause a drastic change in the protein that is made, and in some cases, will cause some pretty significant changes in our phenotype. A mutation on a section of DNA that controls the proteins that make up eye color can cause heterochromia. In heterochromia, spots of irregular shape appear around the pupil that are a different color than the circular ring that is around it. Perhaps a mutation on the DNA caused a different protein to be made in the eye cells, which caused this variance in color. 

Human DNA Extraction Lab

In this lab, we asked the question: How can DNA be separated from cheek cells in order to be studied? During our research, we learned that the protocol for DNA extraction involved three basic steps: homogenization, lysis, and precipitation. We found that it was made possible by means of scraping our cheek cells with our teeth in the presence of Gatorade, adding salt, soap, and pineapple juice, and then finally applying a layer of cold alcohol at the top. The DNA floated to the alcohol with ease.

In order to break down the cell walls/membranes, plasma membranes, and nuclear material in the first step homogenization, the cell tissue must be submerged in a polar liquid, which in our case, was Gatorade. Inside the mixture of our saliva, Gatorade, and cheek cells, we could see the DNA a little bit better because of the breaking down of the cell membranes, plasma, and nuclear material. After adding soap, salt, and pineapple juice to the mixture, 95 percent isopropanol alcohol is layered carefully to the top of the mixture, and since alcohol is nonpolar and DNA is polar, the DNA falls out of the solution as a precipitate at the interface of the two solutions. After pulling it out of the alcohol layer, our DNA has been extracted.

While our hypothesis may have been supported by our data, there could have been possible errors due to the fact that many of the steps didn't have exact amounts of materials we were supposed to add. This could have affected the results because if we didn't have the right amount of something to add to the solution, the DNA may have not been able to be extracted properly. Also, we were supposed to come up with the procedures by ourselves, so if we did something that was not in the correct order, that could have messed up the process of extracting the DNA properly. I think that next time, maybe more precise amounts should be added to the procedure and the students should actually get the full procedures to prevent the possibility of just wasting materials by not being able to do the actual procedures.

This lab was done to demonstrate how DNA could be extracted from cheek cells and that DNA is not as complicated and unreachable as we may think. From this lab, I learned about concepts such as homogenization, lysis, and precipitation, which helps me better understand the concept of DNA as a whole. Based on my experience in the lab, if cloning is invented, I would definitely know how to extract my DNA to create a clone.