Unit 5 Reflection

      This unit was about how information flows from DNA to RNA and then to proteins. We learned how DNA codes for all of our traits and the process of protein synthesis and how ribosomes read RNA, which gives us the phenotypes we have, and even mutations, of which there are two types, point and frameshift. The processes involved in this "central dogma" of biology include protein synthesis, which is a two part process of transcription and translation where DNA is copied and the nitrogen bases are read, semi-conservative DNA replication, where the two new strands contain half of the original strand, and DNA regulation, which determines which genes are expressed and which aren't.

http://thebiologyprimer.com/transcription-rna-processing-and-translation/

       In my opinion, the majority of the concepts in this unit was easy to understand. I really understood the process of protein synthesis and how amino acids are made. I also know the different kinds of mutations fairly well, as the protein synthesis lab really helped me understand what exactly happens to the DNA and the resulting protein. Some concepts were a little more vague at first to me, like the gene regulation and expression in. Now I understand the process of gene regulation in prokaryotic cells, but I still need to review how it works in eukaryotic cells. I want to learn more in detail about protein synthesis and why the nitrogen bases in DNA pair up the way that they do. 

      I think that I am understanding the concepts even more than I did last unit. I am definitely putting in more effort into trying to understand what we learn, rather than just blindly memorizing facts like I used to do. According to the VARK questionnaire that I took last unit, I learn best by reading and writing, so I took the approach of reading over my notes and writing my own notes on what I think that I need to study for the test. I remember things better if I physically write them with my own hands, so that is how I've started to prepare for the final exam. I think in the future I still need to work on my time management in terms of studying, as I usually try and cram in the last few days before a test.

Protein Synthesis Lab

      In this lab we asked the question, "how does the body produce proteins?". Protein synthesis has two stages, transcription and translation. Transcription happens first in the nucleus. First, a copy of a section of DNA is made, called RNA, and the base thymine is replaced with uracil. Then the RNA moves to the cytoplasm, where translation happens. In the cytoplasm, a ribosome reads three base pairs at a time, this is called a codon. Each codon codes for a different amino acid. The amino acids bond together to form a long chain, which become a protein.

http://www.yourgenome.org/facts/what-is-a-mutation

      A mutation is any change in the sequence of the DNA. There are point mutations and frameshift mutations. A substitution is a point mutation that substitutes one base pair for another. For frameshift mutations, insertion is where an extra base pair is inserted, and deletion is where a base pair is removed. From the experience with the lab, the frameshift mutations seemed to have a greater effect than substitution. With substitution, only one of the amino acids is changed, but with insertion and deletion, the whole sequence is shifted, which can completely change the codons and they amino acids produced. Also if the mutation is earlier in the sequence, then it has a greater effect, as the rest of the sequence after the mutation is shifted, resulting in more change. However if a mutation happens later in the code, than it only effects the DNA after, which is a smaller amount.

http://study.com/academy/lesson/insertion-mutation-diseases-examples-quiz.html

      When I chose my mutation, I chose to do a substitution to see if it could have a huge effect like a frameshift mutation. I changed the DNA at the very beginning, resulting in the absence of a start codon, so there was no protein. I think having the mutation towards the beginning of the code has a higher chance of making a bigger change to the amino acid sequence.

      Mutations are very common and they can have little to no effect, or they could have a very dangerous or even fatal effect. Mutations effect the amino acids in proteins, so they could possible alter how your body functions, and cause diseases etc. Hutchinson-Gilford Progeria Syndrome is a very rare disorder caused by a mutation on the LMNA gene which produces the Lamin A protein. Progeria caused rapid aging in children, and children usually die of heart disease at around age 14. Symptoms can include aged skin, loss of body hair, stiff joints, and more. 

https://www.sciencenews.org/article/family-takes-progeria-%E2%80%98life-according-sam%E2%80%99

DNA Extraction Lab

      In this lab we asked the question: How can DNA be separated from cheek cells in order to study it? We found that we can extract DNA through a three step procedure of homogenization, lysis, and precipitation. We collected the cells with gatorade and added salt. We then added soap to lyse, or rupture, the cell membrane so all the contents of the cells released into the gatorade. We then added pineapple juice, which is a protease that breaks down the histones (proteins) that the DNA wraps itself around. Lastly we added a nonpolar liquid, alcohol, which made the polar DNA separate from the gatorade solution, successfully extracting DNA from our cheek cells.

     

      While our observations supported our hypothesis, there could be possible errors due to failure of properly inverted the test tube to mix the contents. If the tube was inverted too quickly, then air bubbles could have formed, and according the information about DNA extraction, air bubbles can get caught in the double helix structure. In the procedures I recommend saying to invert the tube slowly. Failure to add the alcohol in could also cause errors. If the alcohol was added too quickly, than it would mix with the gatorade, which would not allow for the DNA to separate out into a polar solution. I recommend to hold the test tube at as much of as angle as possible and to pour the alcohol very carefully and slowly.

      This lab was done to demonstrate the process of DNA extraction and what happens to the DNA through this process. From this lab I learned how to extract DNA with materials that anyone has access to. Based on my experience from this lab, if I ever entered a field like genetics or forensic science, I could use this procedure to extract DNA from important or useful sources.

A clump of DNA