![]() Partners: Jackie Gibson & Gray Martucci DNA replication is the process in which DNA or deoxyribonucleic acid undergoes to pass on inheritable traits or genes. DNA is the basis of all life and provides “instructions” as to what certain organisms will become and the genetic traits they will carry. DNA’s shape is vital to its functions; DNA forms in a double helix or ‘twisted ladder’ when put into layman’s terms. Each side of the double helix is composed of alternating deoxyribose and phosphate molecules. The two sides of the DNA molecule run opposite one another so that there are never two 5’ or 3’ at the same end. The 5’end is where a free phosphate group is attached to deoxyribose sugar and the 3’end is where a free hydroxyl group is attached to a deoxyribose sugar. In between the two sides of a DNA strand there are 4 different nitrogenous bases which attach the two sides together and make the DNA molecule one. The four different nitrogenous bases are: adenine (A), cytosine (C), guanine (G), and thymine (T). Adenine can only ever attach to thymine and guanine can only attach to cytosine. The bonds which hold together the sides of a DNA molecule are much stronger than the internal bonds between the nitrogenous bases. This is because the bond between the deoxyribose and phosphate molecules is a covalent phosphodiester bond and the bonds between the nucleotides are hydrogen bonds. The first step in DNA replication begins with an enzyme known as helicase. Helicase is able to “unzip” the two sides of a DNA molecule by breaking the hydrogen bonds between each of the bases. As helicase unzips it creates a leading strand and a lagging strand. The leading strand is always of the 3’ to 5’ orientation because it is more efficient for the cell to copy this way. Once the strands are separated into leading and lagging strands RNA primase starts to prime the strands for replication. The RNA primase continuously primes the leading strand while the lagging strand gets primed in small chunks due to the differing orientations of strands. After DNA is primed DNA polymerase III attached nucleotides to already existing bases. On the lagging strand, this process of replication is not as smooth because the DNA polymerase can only copy in the 3’ to 5’ direction. Because of this the DNA polymerase works backwards and fills in the chunks that are known as Okazaki fragments. Since there is a space between fragments another enzyme is needed to help fill in the gaps, this enzyme is known as DNA ligase. The final step of DNA replication is for DNA polymerase I to go back and replace the spots on the lagging strand where the RNA primer placed uracil instead of thymine. Bibliography Cs.boisestate.edu, cs.boisestate.edu/~amit/teaching/342/lab/structure.html. “The Purpose of Antiparallel DNA Strands in the DNA Molecule.” Bright Hub, 13 Nov. 2008, www.brighthub.com/science/genetics/articles/14869.aspx. “The Purpose of Antiparallel DNA Strands in the DNA Molecule.” Bright Hub, 13 Nov. 2008, www.brighthub.com/science/genetics/articles/14869.aspx.
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Partners: Allan, Nikhil, Jackie
Introduction: The purpose of this lab was to learn the process of electrophoresis using the dyes from M&Ms. This lab is a first trial before we use DNA in our future experiments. We can learn what charges molecules in dye have and what their mass is. Procedure: First we formed our agarose gel using a mold which we poured the liquid agarose into. We then used a dye extractor to get the dyes off of our M&Ms. We put the dyes into small tubes. The next day our gel had solidified. We removed the tape and Jackie accidentally broke our gel by dropping it. Only two of our wells were still usable. Lane one had dyes from a green M&M and lane two had the dye of the brown M&M. We used a voltage of 100V for 15 minutes. The two lanes ran correctly while the others didn't. We had to borrow data from another group because our data was not correct. The first lane was blue, second was red, third was the control, fourth was the 2nd control, fifth was the 3rd control, sixth was the 4th control. They then ran the experiment. Result: All of this date is from Olivia Studebaker and Tajel Patel. They used a photo and measured the distances. The total distance was 1.5 inches. 1st sample: .56 inches, 2nd sample: .94 inches, 3rd Sample had red blue and yellow, blue went .56, red went .94 and yellow went 1.06. 4th sample had blue and yellow, blue went .56 and yellow went .88. 5th sample had blue, red and yellow, blue went .56 red went .94, and yellow went 1.06. The 6th sample had blue and red: blue went .56 and red went .94. Conclusion: This experiment showed us that electrophoresis can be used to separate small molecules using mass and charge. We learned what dyes make up other dyes. Size and charge was determined by looking at the final placement of the dyes in the gel. If a gel moved positively its charge was negative. Every dye tested matched the control dyes so we were able to correctly identify the dyes in each one tested. Dye from the red M&M matched the Red 40 and dye from the blue M&M matched Blue 1. Discussion: Charge and size are the only thing that we could observe through this lab. Charge affects the distance traveled greatly. Being smaller also allowed a dye to travel farther through the gel. So both the charge and the size of the molecule can affect how far a dye can travel through the agarose gel. Other control dyes besides agarose include: Carminic Acid, Betanin, Fast Green FCF, and Citrus Red 2. Betanin and Fast Green FCF have negatively charged ends allowing them to move through the gel. Citrus Red and Carminic Acid don't and would not move. DNA is often separated using this method. A molecule with a mass of 600 Daltons will move farther than something with a mass of 5000 Daltons. Electrophoresis allows scientists to separate things too small to do by hand and gives them the ability to learn more about DNA. Bibliography: “What Can Gel Electrophoresis Be Used For?” It Still Works | Giving Old Tech a New Life, itstillworks.com/can-gel-electrophoresis-used-5122149.html. “Unified Atomic Mass Unit.” Wikipedia, Wikimedia Foundation, 24 Jan. 2018, en.wikipedia.org/wiki/Unified_atomic_mass_unit. http://ceprap.ucdavis.edu/wp-content/uploads/sites/408/2016/10/Gel-Electrophoresis-of-Dyes.pdf What would you do if you could make your kids taller, faster, stronger or even smarter? That is one of the questions that humankind will have to answer in the near future as gene editing becomes less of an experiment and more of an everyday topic. In our class we discussed this topic and there was a split in that some did not want to mess with their children at all while others would be fine with the possibility. I was on the side that whatever the situation was in the future was what I was going to be okay with. I'll explain, if other kids in your child's grade are a year older because they were held back, would you hold your kids back? I would. If the social norm was to edit our kids to make them better, then I would be comfortable changing the genome of my kids for the better. Not to give them an unfair advantage but to give them a fair chance.
What will you decide for your children? How far can this gene editing go? Would people be willing to agree to only use gene editing to protect their children from genetic disorders? How far away are we from gene editing being a more mainstream thing? Is choosing the gender of your child unethical? |
AuthorMy name is Kellen Mayberry and I go to Holland Hall. Over the next 4 months I will be looking into the science and ethics of an upcoming field known as genomics. I have always had an interest in science and with how things work. It will be exciting to get to know how we as human beings function and why we are the way that we are. ArchivesCategories |