Unit 5 Reflection

In this Unit, we learned about the central dogma of biology, how protein is made, and about mutations. The central dogma of biology is that DNA becomes RNA which becomes proteins which eventually become a organism. But in order to make the protein it has to go through the process of transcription and translation. Transcription is the process of RNA polymerase reading and copying DNA code into a temporary mRNA copy. This mRNA then travels to the cytoplasm to be translated. Once the mRNA arrives at the ribosome, the ribosome reads the mRNA in pairs of 3 or codons to correspond to an amino acid. Once the whole sequence has been translated, there is a string of amino acids left, or a protein. However, during this process bases in the sequence can be changed, which is what we call a mutation. Some types of mutation are insertion, deletion, and substitution. Insertion means inserting another base into the sequence, deleting means deleting a base, and substitution means substituting a base pair for another base pair. 

In this unit some of my weaknesses were fully grasping the concept of translation to create a protein. It took me a while to understand why that process was needed and how to exactly translate the DNA sequence itself. However some of my strengths were learning about mutations because that was a concept I could pick up really quickly. But, for translating DNA I was able to understand it much more because of the protein synthesis lab we did. In that lab we practiced translating DNA and thoroughly understood the process of protein synthesis.

After this Unit, I think I have grown as a learner. I would classify a good learner as one that learns from his or her mistakes and grows because of it. I think I would fall into that group. In the beginning of the year, I did not have the correct strategies to learn. I would wander off during vodcasts and not really pay attention and that had bad outcomes for me. However now I actively listen and my grades have reflected that. Overall this Unit has taught me a lot and has made me a better student. 

Protein Synthesis Lab

In this lab we asked the question, How does the body produce proteins? Through this experiment we got a thorough understanding on the process of making proteins. First, a section of our DNA is copied by an enzyme which produces mRNA. Then, once the mRNA is produced it leaves the nucleus and travels to the cytoplasm. That process is called translation. The next process is transcription where the mRNA bonds with a ribosome. The ribosome then reads the sequence of the bases on the RNA 3 at a time, or in codons. Each codon corresponds with an amino acid, and to determine which amino acid goes with each codon, the codon is read by RNA polymerase. Once it is determined which amino acid goes with each codon, all the amino acids are bonded together making a protein.

However, during this process bases could be changed around which is called a mutation. There are many types of mutations such as insertion, deletion, and substitution. Insertion is when an extra base is added anywhere in the sequence. Deletion is when a base in the sequence is deleted. Finally, substitution is when a base in the sequence is substituted for something else. In the lab, we tested out the effect of these mutations in the gene, and what we have found is that insertion and deletion generally causes the most damage especially if the change happens in the beginning of the sequence. The reason it had more effect if the mutation is in the beginning of the sequence is because that one change can alter everything after it, but if the change was at the very end of the sequence there is not much to alter after it. Also substitution didn't have as big of an effect because it only changes the codon that it is part of.

In step 7 of the lab we got to choose our own mutation. The mutation I chose was the deletion of the very first base. This had a much more dramatic effect than any of the mutations I had experimented with before. This is because since the base changed was the first one, not only did it change all the codons after that, but it also caused the fourth codon to be one that coded for stop so the sequence was only 4 amino acids long. This clearly shows that where the mutation occurs has a big effect. Since my mutation was in the very beginning of the sequence, it cause a lot of damage.

This relates to my life, because there could be mutations in my body that could possibly give me a disease. Mutations can be beneficial, but they can also be detrimental. For an example, a disease caused by a mutation is Tay-Sachs. This disease occurs when there is a defective gene on chromosome 15,  causing nerve cells in the brain and spinal cord to die.

DNA Extraction Lab

In this lab we asked the question: How can DNA be separated from cheek cells in order to study it? We thought that if DNA can be separated from a solution in the form of precipitate, then when alcohol is added DNA will unwind. To test our hypothesis we first began by homogenizing our cheek cells with polar liquid, in other words we began by scraping our cheek cells and swishing it in our mouth with Gatorade. Next we added salt, and soap which lyses or breaks down the cheek cells. Then we added pineapple juice which acted as an enzyme to break down any if the proteins that the DNA was wrapped around. Finally we added cold alcohol to the mixture and let it sit for 5 minutes. When we observed it after those 5 minutes were up we saw precipitate beginning to the top of the solution. This precipitate was the DNA that had been extracted from our cheek cells. This supports my hypothesis because after alcohol was added, precipitate started to form at the top of the solution.

While our hypothesis was supported by our data, there could have been errors due to not following the instruction very carefully. One example of an error we made is adding the wrong amount of Gatorade. This is because since we didn't have a measurement of how much Gatorade we were supposed to drink, some people had more Gatorade in their solution than others. This could have effected the ratio of Gatorade to other things like pineapple juice and resulted in little to no precipitate produced. A way to eliminate this error is by having a set measurement of Gatorade so everyone ends up having the same amount. Another possible error is not doing the lab in the right order. This is because for this lab all the steps were out of order and we had to put it back in the right order. It is very possible that we may have put it back together in the wrong order. For this error the only way of eliminating it would be to give us the instructions already in the right order or when we put it together to tell us whether it is correct or not.

This lab was done to demonstrate how DNA is separated for studying purposes and that DNA can be found everywhere in your body including places like your cheek cells. From this lab I learned the process of extracting DNA and all of the new vocabulary that is associated with it such as lysis and homogenization.  Based on my experience from this lab, I now know how to extract DNA from cells if that is every required of me in the future.