Unit 5 Reflection

In unit 5, we learned about how our genetic code determined who we are and the great importance of our DNA. Deoxyribonucleic acid, or DNA, is the basis of all life and is made up of millions of nucleotides, which are made of a nitrogen base, a phosphate group, and a sugar(deoxyribose). In 1953, Francis Watson and James Crick discovered the structure of DNA: a double helix. This double helix shape helps the DNA pack together tightly and supports the structure as well. Each nucleotide bonds covalently with each other, creating an antiparallel structure, meaning the 5' and 3' carbons go in opposite directions. Nitrogen bases with double rings are called purines, adenine and guanine, and single rings are called pyrimidines, thymine and cytosine. This basic genetic code is a simple system that allows individuals have special qualities and unique features
. The process of replicating DNA is a simple concept, where helicase unzips the DNA and DNA polymerase adds the matching nucleotides to the unwound strands creating two new genetically identical cells.

One of the most important concepts of our DNA is the central dogma of biology. The central dogma of biology is the process from DNA to protein, where DNA is transcribed into RNA and RNA is translated into amino acids and eventually into proteins. During transcription, the DNA unzips and RNA polymerase creates a complementary RNA strand and once finished mRNA exits the nucleus into the cytoplasm. During transcription, ribosomes read the mRNA three bases at a time, in codons, and turns them into amino acids and eventually protein. This process is especially important, because without it would be impossible for life to thrive. One of the most important subjects in genetics is gene expression and regulation. All cells in our body have the same DNA, and yet they only use the minimum amount of DNA that they specialize in for one reason: to save energy. This is the reason why you don't have ears on your chest and why fingers aren't on legs because the appropriate genes are only turned on at the appropriate times.

Although unit 5 was short, I grew a lot as a student. The main thing that usually helps me with the unit is understanding the concepts and applying it to the real world. For example, in protein synthesis section I applied it into real life, as proteins are everywhere and help us get through life every day. Last unit we took the VARK questionnaire, and I learned that I learn best visually over any other method. After thinking about this a little bit, I realized that I was a very artistic person, therefore a visual learner as well. Overall, in this unit I learned a lot about genetics as well as myself.

Protein Synthesis Lab Conclusion

The process, or procedure, of creating protein from DNA is called protein synthesis and requires several steps. First, the DNA unzips and the RNA polymerase begins to read the DNA, creating a complementary strand of RNA. Once the RNA is created, the mRNA exits the nucleus for the cytoplasm, and eventually bonds with a ribosome. The ribosome then starts to read the mRNA three bases at a time, called codons, creating amino acids for the corresponding codons. Finally, once the ribosome finishes reading the mRNA and creates the amino acid chain, the amino acids begin to fold into the final protein. The end result is a unique protein made of several amino acids.

Mutations can range from being lethal to very lethal, especially if the DNA is changed drastically. There are several ways that DNA can be altered, and some are more lethal than others. The least lethal, or least effective is a substitution, where one base is substituted for another, and the most it can alter is one codon, barely affecting the protein. The next two are frameshift mutations and can affect the DNA sequence drastically. The first is an insertion, where one or more bases are inserted into the DNA, and the second is a deletion, where one or more bases are taken out of the DNA. Both these mutations will shift every base after them and are more lethal if the insertion or deletion is at the beginning of the DNA sequence.

In step 7 I chose to do a deletion of two bases, which turned out to be very effective. The protein was affected drastically, as a result of the deletion of only two bases, the entire protein was deleted because the first codon was a stop codon, rendering the protein non-existent. The bases that were deleted were in the front of the DNA sequence, therefore causing more damage because it shifted almost all of the bases, changing the protein in the process.

Proteins make our body work, but it there is a mutation in the protein, the effects could be drastic. A good example is progeria, a rare disease that causes accelerated aging. People affected by this disease can die at the age of 13 but can live up to their twenties, and only about one in eight million are affected by this disease. The disease is caused by a mutation in the LMNA, a protein that supports to the cell nucleus, and shows the horrible effects that just one protein can cause.

Citations:
http://io9.gizmodo.com/10-unusual-genetic-mutations-in-humans-470843733
https://commons.wikimedia.org/wiki/File:Ribosome_mRNA_translation_en.svg
https://commons.wikimedia.org/wiki/File:Missense_Mutation_Example.jpg
https://simple.wikipedia.org/wiki/Progeria

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 could be achieved through a series of steps that extracted cheek cells and separated the DNA, making it observable. The first thing we did was we homogenized cell tissue with a polar liquid, which in our case was Gatorade, which we swished around our mouths, extracting the cell from the inside of our cheeks. After taking the Gatorade/saliva mixture and mixing salt into it, we added soap into it, in order to lyse, or rupture, the cell membrane, in effect releasing the contents of the cell into the mixture. Next, we used catabolic proteases found in pineapple juice to further break down proteins in the DNA called histones. Finally, we layered alcohol over our mixture, and because alcohol is nonpolar whereas the DNA is polar, the DNA falls out of the solution as a precipitate right in between the layers, eventually floating to the top. This data supports our claim because it shows that DNA can be in fact extracted and separated from cheek cells, using scientific methods to retrieve safely and easily.

While our hypothesis was supported by our data, there could have been errors in several parts of our experiment. First, when we were pouring the pineapple juice into our solutions, bubbles were formed at the top of the solution, which could have affected the yield of DNA that ended up having. In addition, during the addition of alcohol over our Gatorade mixtures, some of my other group mates poured the alcohol in too fast, therefore causing the two layers to mix, and affecting the yield and the outcome of their DNA. Due to these errors, in future experiments I would recommend having an easier method in transferring over solutions, such as using small graduated cylinders to measure and pour solutions over carefully and accurately. Furthermore, for pouring in alcohol, or any solution into a small test tube, funnels could be used to prevent spills.

This lab was done to demonstrate the concept of DNA and how it can be found anywhere in your body. From this lab I learned how to extract and separate DNA from the inside of an organism's cheek, which helps me understand the concept of DNA and its abundance inside the human body, while also giving me a physical observation of DNA. Based on my experience from this lab, I could use these methods of extracting DNA to do other things, such as extracting other organism's DNA or studying the effects of DNA and how
it is important to the scientific world.