Unit 5 Reflection

Unit 5 was all  about DNA, RNA, and their functions. DNA is a double helix structure that has nucleotides that code for proteins. The nitrogen bases are Adenine, Thymine, Guanine, and cytosine. A and T pair up while G and C pair up.

When RNA needs to be made, an enzyme called RNA polymerase unzips the DNA and pairs a nucleotide with each strand of DNA. In RNA, the base Thymine is replaced with Uracil (U). This single stranded mRNA breaks off and travels through the cytoplasm to a ribosome. In the ribosome, the RNA is read three base pairs at a time. Each three bases codes for a codon and each codon represents an amino acid. The amino acids keep adding on to the polypeptide until a stop codon is reached.

A mutation is a change in the genome. Mutations can either be harmful, give benefits, or have no affect at all. A point mutation is a mutation that changes on or two bases. A substitution is swapping one base out for another. A frameshift mutation is a deletion or insertion of a base and changes every codon that comes after the mutation.

Another concept is gene regulation and expression. In any given cell, only a fraction of the DNA is used to express a phenotype. In prokaryotic cells, a repressor is attached to the operator that prevents the RNA polymerase from reading the DNA, but the repressor detaches when lactose is present allowing the gene to be expressed. However, this process is much more complex in human cells.

This unit was not to difficult, as I found the process of making a protein and mutations fairly straightforward. The concept of gene regulation was difficult to understand and it was very complex. This unit helped me understand the last two units better, as they were also about genetics. Making the study guide helped me learn, because if forced me to answer questions and told me what I knew and did not know. This unit has helped me grow as a student, because it made me have to try harder to learn things I did not understand. A question I have about this unit is how the mRNA travels through the cytoplasm to the ribosome without getting lost.

https://commons.wikimedia.org/wiki/File:0323_DNA_Replication.jpg

Protein Synthesis

The creation of a protein is a several step process. It starts with an enzyme unzipping the DNA. Another enzyme then goes along the DNA and reads the sequence and puts a the matching base pair with each base. Instead of matching A with T, it replaces the T with a U. The completed RNA then detaches from the DNA and travels to a ribosome. The mRNA is read and every 3 bases represents a codon. Each codon represents an amino acid. The ribosome goes down the line and reads every codon until it reaches a stop codon. The amino acids then break off and the protein is complete.


Mutations can either change a gene dramatically or not at all. A simple substitution in the DNA either causes one or two codons to change or sometimes, none at all. A frameshift mutation such as an insertion or deletion can cause big changes and change every codon after it. A frameshift mutation at the beginning of a sequence would cause more damage than at the end, because a frameshift causes every codon after it to change. If it occurred at the end, only a few would change.

When I chose the mutation I would like to do on a DNA strand, I chose an insertion. I chose this because it would allow me to stop the translation right after it started. It caused the most change out of all mutations because it didn't allow for any amino acids to be coded for except the start codon. It mattered where th mutation occurred, because it occurred right after the start codon. If it had been towards the end, the amino acids that came before would have still been coded for.

Having a mutation could result in several things. A mutation could result in death, a disease, or nothing at all. We all have many proteins in our body that carry out essential functions such as carrying oxygen in the blood. An alteration to one of these important proteins could have some major consequences. For example, Parkinson disease in often caused by a mutation in one of several genes. It causes loss of control of muscles. Some mutations can guarantee that an individual will develop Parkinson, and another mutation increases an individuals risk of getting the disease.


Works Cited:

Eisen, Jonathan. “Fact Sheet: DNA-RNA-Protein.” MicroBEnet: the Microbiology of the Built Environment Network., Alfred P. Sloan Foundation, 29 Oct. 2013, www.microbe.net/simple-guides/fact-sheet-dna-rna-protein/. 

“What Kinds of Gene Mutations Are Possible? - Genetics Home Reference.” U.S. National Library of Medicine, National Institutes of Health, 6 Dec. 2016, ghr.nlm.nih.gov/primer/mutationsanddisorders/possiblemutations.

“Animal Genetics.” Print Page, web2.mendelu.cz/af_291_projekty2/vseo/print.php?page=315&typ=html.

http://web2.mendelu.cz/af_291_projekty2/vseo/print.php?page=315&typ=html

“National Institutes of Health.” National Institutes of Health, U.S. Department of Health and Human Services, 21 July 216ADAD, www.niehs.nih.gov/health/topics/conditions/parkinson/.

DNA Extraction Lab

In this lab we asked the question, can DNA be separated from cheek cells and if so at what point will you be able to see the DNA. We predicted that it would be possible and the DNA would be visible after the stage where alcohol was added. We found that it is possible to separate the DNA in a process of homogenization, lysis, and precipitation. After the alcohol was added to the solution, the DNA was clearly visible, floating above the solution in the alcohol. This would make sense, because the alcohol is a polar substance and DNA is nonpolar, so the polar substance should draw out the DNA, which is exactly what happened in our experiment.

While our hypothesis was supported by our data, there could have been errors due to mistakes in the procedure and inaccurate measurements. When making our procedure, we placed one of the steps incorrectly, so after pouring in the alcohol and extracting the DNA we had to shake the vile ruining our extracted  DNA. Also, when measuring things like soap and enzyme into the solution, everyone had a different idea of how much to add, resulting in members of the group having different solutions. This could have caused people to have different results, skewing the data. In the future these errors could be avoided if the procedure is given to students and one student does all the measuring to keep it consistent. 

This lab was done to demonstrate how molecules interact with one another and how DNA can be extracted from organisms. This helps me understand the concepts of polar and non-polar and to understand DNA and how it works and interacts with other substances. Based on my experience with this lab, I can apply my knowledge of DNA to other labs and I now know how to create a proper lab procedure from several different parts.