Unit 5 Reflection

Unit 5, named Walking the Dogma, described and went in depth to the function and processes surrounding the DNA in each and every one of our cells. The unit started when we learned about the structure and function of DNA and its code- which was very easy to grasp for me because it was extremely practical. The steps were logical and I felt like watching the videos of the RNA making proteins helped me see what I was learning. DNA expression and regulation, since I could relate it to our bodies, were easy to understand. I think of expression like “that is why it is there” for example having two eyes, and regulation like the opposite, why we don’t have 37 eyes. Though this is a simple example, it helped me relate the science to life. For me, the mutations vodcast was confusing because there were a ton of mutations and things that could go haywire in a DNA. I didn’t know that these all things could happen so it was a bit overwhelming! But, after doing the mutations lab, the concepts made perfect sense and were easy because I tried doing the mutations myself. What made this unit easy was that it was very convenient to try things out and figure out the processes like base pairings and mutations ourselves. And doing the DNA extraction lab towards the end of the unit was also cool and informative to another DNA process. Overall Unit 5 was short and sweet!

Protein Synthesis Lab

To start making a protein, the DNA is transcribed to RNA in the nucleus. Then it is converted into messenger RNA (mRNA) which is sent out of the nucleus to a ribosome. RNA Polymerase pairs the corresponding nucleotides with a RNA strand. In the ribosome, the RNA reads three bases at a time to form codons which code for amino acids. These amino acids are joined together to form a protein. 

In this lab we tested different kinds of mutations that could potentially occur while DNA is being transcribed and their affect on the protein structure. The mutation that caused the least damage to the protein was substitution. This mutation had the least effect on the protein because though the amino acids changed, it was still a complete protein.  The frameshift mutations caused much more damage to the protein because most amino acids were changed and there were extra incomplete codons in the end.


In the lab, after trying different mutation, we were asked to chose the one that would be the most harmful to the protein. I chose deletion, because not only does it change entire amino acids, the end codon is left incomplete. I decided to take out the first C in the DNA sequence, and was left with a completely altered RNA, as expected. 

A mutation that I didn't know stemmed from the genes is sickle cell anemia. It is the result of a point mutation, where one nucleotide is changed for hemoglobin. This causes the hemoglobin in red blood cells to change into a distorted shape and clog the capillaries, cutting off circulation.

DNA Extraction Lab

Conclusion

     In this lab we asked the question, "How can DNA be separated from cheek cells in order to study it?" We found that this procedure involved three steps including homogenization, lysis, and precipitation. We carried this out by mixing our cells in a polar liquid. This breaks down the cell and nuclear membranes of the cheek cell, homogenizing it. Afterwards we added soap to the mixture, initiating lysis which disintegrated the membrane. We used pineapple juice to break down histones found in DNA, causing it to uncoil. This was possible because pineapple juice, like a few other liquids, has catabolic proteases and  enzymes, that help to break down the histones. Finally, we poured cold isopropanol alcohol into our test tube and due to its non-polarity combined with the polarity of the DNA, the DNA became a precipitate and rose to the top of the isopropanol alcohol layer.  This data supported our procedure because, to put it simply, it worked!
     While our hypothesis was supported by our data, there was one vital error that we carried out. After adding pineapple juice and soap, we were supposed to gently invert the test tube 6 times and we chose to do this step after adding the alcohol, so the two layers got mixed. Out of the four people in our group, two people's DNA were ruined because of this. This error happened because we created our own procedure without a more educated approval to tell us when to put each step. Another hypothetical error could have been the time factors. If one gargled gatorade for more or less than thirty seconds or observed for more or less than five minutes, results might be changed though the effect isn't drastic. To minimize these rather small to extremely important details, get a teacher's approval before starting and keep a timer handy!
      This lab was done to demonstrate the process of extracting DNA from a cell. From this lab I learnt how to remove DNA from its original position in a cell which helps me understand the concept of DNA and its structure. Based on my experience from this lab I applied the concepts around DNA and I now have a
 sample of my own!