Unit 5 Reflection

In this unit, we learned about the central dogma of molecular biology. We studied the structure of DNA and its antiparallelness. We also learned about how the enzymes helicase and DNA polymerase are used to copy DNA. In addition to DNA, we also learned about RNA and proteins. We were taught the main types of mutations and their effects on proteins. The labs we did in this module involved extracting our own DNA and simulating the process of going from DNA to RNA to Protein.

I feel that I was able to understand the DNA copying, the Dogma, and mutations vodcasts very well. I am already familiar with the information taught in the dogma and mutations vodcast, but not the copy machine one. Although the enzymes involved in DNA replication were new to me, I think that their roles were quite basic. This probably explains why that set of vodcasts felt extremely easy. However, the gene expression vodcast was slightly tougher than the other ones. This is probably because I am not very familiar with how the operon and gene regulation work. After reviewing the diagram a couple of times though, I had a pretty good grasp of the concept.

I am glad that I learned a lot of new material in this unit. In other units, the number of new concepts were close to zero and weren't very interesting. However, the enzymes and mechanisms involved in the replication, transcription, and regulation of genes I learned about in Unit 5 were really cool. I definitely think I am a better student today than at the start of this unit. This is because for this unit, I really had to try to understand some of the concepts, compared to other areas we have learned about that I was already too familiar with to apply studying methods.

I want to learn more about the operon and gene regulation. I still have questions involving gene regulation in eukaryotes. I might research these processes for the 20 time project, but I am not sure.

For this unit, I learned more about the operon by searching up other diagrams that felt more descriptive to me. This helped because I am a multimodal learner (mostly visual and reading), and the images were labeled diagrams.


DNA floating on top of alcohol from-DNA Extraction Lab

a deletion mutation from-Protein Synthesis Lab

Protein Synthesis Lab Conclusion

     In order to make protein, the a gene found on DNA must me copied into mRNA (transcription). This involves RNA Polymerase, which constructs an mRNA strand complementary to the DNA sequence being scanned. Also, instead of using Thymine, RNA uses another pyrimidine: Uracil. This strand of mRNA then exits the nucleus and arrives at a ribosome (translation). Here, tRNA molecules carrying the amino acid corresponding to each codon, a set of 3 bases, connect the amino acids in the dictated order. Once the polypeptide chain has formed, it folds and gets packaged in the Golgi Apparatus. This protein is then used either inside or outside the cell for a variety of purposes.



     In my opinion, insertions and deletions of 1 or 2 bases at the start of a sequence and the start of a codon make the largest difference. It makes a major difference when it is 1 or 2 bases because that creates a frameshift. If 3 were inserted, then a new amino acid would be produced but the rest would remain the same. It makes a large change when at the start of the sequence because then Methionine may not be read, and all of the following codons are frameshifted. It is also important for it to be at the start of the codon, because sometimes if the base change is at the end of a codon, it may not change the amino acid that is made. The mutations that makes the least change are frameshift mutations of 3 bases, frameshift mutations near the end of a gene, and substitutions of the last base in a codon. The first one makes a small difference because if 3 are inserted/deleted, it just adds/removes an amino acid. The second mutation makes a minor difference because if the frameshift is near the end of a gene, it doesn't frameshift that many codons. Also, substitutions of the last base in a codon don't make much of a difference because often the produced amino acid is not different.

^A lot of these hemoglobin variants are caused by a single base substitution

    In step 5, I chose to make an insertion at the very start of the sequence. The result was that there was no "start" codon, and no "stop" codon. This is a drastic change from the other mutations because in step 5, no protein was produced at all. This frameshift mutation at the start of the gene shows that the location of the mutation is very important.


    If I had a severe mutation that affected an important protein like actin or collagen, I could have muscular or skin defects. These may have a major impact on my life, like preventing me from playing a sport or engaging in high physical stress activities. One mutation that affects collagen is called "Ehlers-Danlos Syndrome". It has a variety of levels, but usually causes hypermobility, stretchy skin, and slow skin healing time. These symptoms make sense because collagen is a structural fiber present in skin that gives skin its ability to stretch and compress.

DNA Extraction Lab Conclusion

     The problem we tried to solve in this lab is, "How can DNA be removed from a cell?". DNA can be removed from cheek cells by using 3 steps: homogenization- removing and dispersing the cells in a liquid, lysis- breaking the cell membranes and other proteins down so DNA is accessible, and precipitation- using a polar liquid to get the DNA to fall out of the solution. When we used gatorade to homogenize our epithelial tissue, soap and pineapple juice to lyse that solution, and alcohol to precipitate the DNA out of the solution, we were able to extract our DNA. The DNA floated from the gatorade solution to the top of the alcohol, and we can be quite sure that it is DNA due to its stringiness and the fact that it precipitated out of the homogenization/lysis solution. The reason why this evidence verifies my claim is that I followed the exact steps outlined in the claim and found the expected result.

    Although I can't find any possible errors in this experiment, there are a couple of things that may have prevented me from getting the optimal results. One possible mistake is that I didn't scrape my cheeks enough. This may have resulted in not getting a lot of cells and consequently not much accessible DNA. I also may have used too little soap/pineapple juice. If I didn't use the right amount of soap, I may have only broken open a few cells and only received a small amount of DNA.
     The purpose of this lab was to understand the lab process of splitting open a cell to get to the DNA. The process of DNA extraction relates to how DNA copies itself. If DNA was unable to replicate itself, then there wouldn't be so many cells with so much of it. The lack of DNA would prevent us from being able to see it (and prevent us from surviving). This skill of DNA extraction may be applied to various contexts such as jobs at genetics companies or research facilities.

In this image, the yellow material at the top of the test tube is my DNA. The clear liquid beneath it is a polar liquid used for precipitation (alcohol). The yellowish liquid under that is a combination of polar liquid for homogenization (gatorade), and liquids used for lysis (soap and pineapple juice).