Science Notebook NEW

Who Murdered Romeo and Juliet:

Lab Report

Friar Vs. Facts Introduction: “We [humans] are all 99.9 percent the same, DNA-wise” (Genome News Network). Although all humans have almost identical genomes, that 0.01 percent variation allows us to completely differentiate each individual. Forensics labs all over the world use DNA testing to determine who the murderer is in many crime cases. Based on DNA testing and comparison to killer DNA found at the crime scene, it is undeniable that Friar Laurence murdered Romeo and Juliet. Purpose: Who killed Juliet Capelet on the night of January 10, 2017? Hypotheses: If Friar Laurence wanted to bring the Capulets and the Montagues together then he could have killed Romeo and Juliet because the marriage was not going to work and he thought their deaths would bring the houses together. If we test all of the suspect’s DNA, then we will find that Friar Lawrence is the murderer, because his DNA segments will travel at the same speed and will line up to the killer’s DNA found in the murder scene. Materials: 2 teaspoons 0.9 percent salt water Dixie cups 9 large test tubes (1 for each DNA sample) 15 ml of palmolive detergent and 45ml of water 2 teaspoons 95 percent ethanol, cooled 9 small test tubes  (1 for each DNA sample) 5 μl methylene blue solution for each DNA sample (1 L of water to 2 ml of methylene blue) Pipette and disposable pipette tips Baking soda Deionized water Glycerin Cold 95%  Ethanol Micro test tube Hot plate Stir rod Micro pipette Procedure: Extracting Dna From Each Suspect Murder suspect will complete this procedure.  Swish 2 teaspoons (10 ml) 0.9 percent salt water in your mouth for 30 seconds. This amount of swishing will actually become quite laborious -- hang in there! Spit the water into your cup. Make your soap and water solution (enough for all your DNA samples) Using a large test tube containing 15 ml of liquid detergent to 45 ml of water Take 5 ml of each sample of DNA that you plan on collecting and place them in their own test tube. Be sure to label each test tube carefully. Add 5 ml of your mild detergent to each test tube. Cap tube and gently rock it on its side for 3 minutes. The detergent will break open the cell membrane to release the DNA into the soap solution. Do not be too vigorous while mixing! DNA is a very long molecule. Physical abuse can break it into smaller fragments, a process known as shearing. Open and slightly tilt the tube and pour 1 teaspoon (5 ml) of the chilled 95 percent ethanol down the side of the tube so that it forms a layer on the top of your soapy solution. Allow tube to stand for 1 minute. Results should look similar to Sample #1. Pull 0.25 ml DNA from the top of the test tube into a micro test tube. Your DNA should stay solid in this solution. Using the disposable pipettes , add 0.25 ml methylene blue solution for each DNA sample Add one drop of glycerin to DNA/methylene blue solution.  (Be sure all micro tubes are labeled clearly) Making the Gel Box The first step in the experiment is to make the buffer solution that you will use for both making the agarose gel and running the samples. The buffer should be a 1% solution of baking soda. To make this, combine 2 grams (g) of baking soda with 200 mL of bottled water in one of your bowls and stir well. (If you don't have a kitchen scale, 2 g of baking soda is approximately ½ teaspoon.) Make a 1% agarose gel solution by combining 1 g of agar powder with 100 mL of your buffer solution in a microwave-safe bowl. (If you don't have a kitchen scale, 1 g of agar is approximately ¼ teaspoon.) Heat the agar solution in a microwave to dissolve the powder. Stop the microwave every 10-15 seconds to stir the solution. When you see that the solution is starting to bubble, remove it from the microwave. The solution should be translucent. Make sure to watch the agar solution carefully and remove it promptly from the microwave; when it gets hot it will easily bubble over. Remove the stainless steel wire electrodes from the gel chamber. Insert the Styrofoam comb into either end of the gel chamber, leaving approximately 0.5 centimeters (cm) between the end of the box and the comb. Gently pour the agar solution into the gel chamber. Add just enough solution to the box so that the comb teeth are submerged approximately 0.5 cm. If the gel is too thick, it will be difficult to observe good separation of the food coloring dyes. Wait until the gel solidifies, which may take at least 30 minutes at room temperature. Tip: When the gel is set, it should be firm to the touch and wiggle like solid jello. Running the DNA Make new buffer solution: combine 2 grams (g) of baking soda with 200 mL of bottled water in one of your bowls and stir well. Pour your buffer solution over the solidified gel. Add enough buffer to submerge the gel. Gently pull the comb out of the gel. Be sure not to remove the comb until you are sure that the agarose gel is completely set. The resulting wells will be used as reservoirs for your samples. Using the butter knife, carefully cut a thin slice of the gel from the top and the bottom to make room for the electrodes. Re-attach the stainless steel wire electrodes. Using a micropipette, fill each well in the gel with a each suspects DNA solution Using the alligator clip leads, attach the battery pack to the wires resting on the gel chamber. The positive terminal of the battery pack should be connected to to the clip farthest away from the DNA samples. Before turning on your electricity double check with Neto. You will be setting machine to       150 V. BE SURE NOT TO TOUCH OR DISTURB BOX DURING THIS PROCESS. You should see bubbles forming around the electrodes in the buffer as the current passes through them. Consider using time-lapse to record your results. Data Table: Length of DNA of each suspect Suspects: Length of DNA (cm) Segment 1 (cm) Segment 2 (cm) Killer 3.00 1.45 2.3 Paris 1.00 1.73 2.75 Friar Laurence 3.00 1.45 2.3 Capulet 3.75 1.6 3 Montague 2.75 1.2 2.3 Lady Capulet 1.50 0.4 0.9 Juliet 2.00 1 1.3 Benvolio 1.75 0.7 1.05 Romeo 2.50 1 2.2 Since our data was inconclusive, this is an example of what our data may have looked like Identify the Independent and Dependent Variable: X: Suspect’s DNA Y: Length of DNA Graph: Conclusion: Based on DNA testing it can be concluded that Friar Laurence killed Romeo and Juliet. If our experiment had been conclusive and showed data, we would have seen something similar to the following; the killer’s DNA (segment 1: 3cm, segment 2: 2.5cm from first segment, ect) and Friar Laurence’s DNA (segment 1: 3cm, segment 2: 2.5cm from first segment, ect). An example of a different suspect’s DNA might have looked something like (segment 1: 1.5 cm, segment 2: 4.5 cm away from the first segment). In continuation the pattern for both the killer and Friar Laurence would have matched identically for each segment along the gel box because they are both in fact the same DNA. Compared to the other DNA samples in the gel box they would not have matched up to the killer’s DNA. Each segment shows part of the DNA broken up and in samples that have segments at the same points means the DNA matches.

Our original hypothesis “If Friar Laurence wanted to bring the Capulets and the Montagues together then he could have killed Romeo and Juliet because the marriage was not going to work and he thought their deaths would bring the houses together. And our scientific hypothesis; If we test all of the suspect’s DNA, then we will find that Friar Lawrence is the murderer, because his DNA segments will travel at the same speed and will line up to the killer’s DNA found in the murder scene.” were correct in predicting that Friar Laurence was the murderer. The conclusion supports the fact that Friar Laurence was the murderer and while we can not conclude his motive based on this lab, we know that he was the murderer based on our visual scientific evidence. Despite the fact that our lab did not give us the ability to see our results we learned a lot from it. Some mishaps included leaving the comb in the gel box too long, which lead to it tearing out a large portion of the box when pulling it out. Additionally, we used steel wire instead of stainless steel which caused the rusting in our gel box and clouded our results. Next time we would need to make sure that the DNA collected was in larger concentration and placed more precisely into the gel box. While our lab was not conclusive due to the errors, if it had worked, as a class we would have had conclusive results because we ran multiple of the same experiment. Following the same procedures (including using steel instead of stainless) someone would have reached the same results as our lab in that it would have all rusted. If someone followed the lab procedures we did properly, they would have had clear, conclusive results. DNA: Notes DNA is a molecule found inside the nucleus Would up as a chromosome 99% of DNA in humans is the same Double helix 5 carbon sugar phosphate groups C & G are always paired A & T are always paired Purines are G and A which have 2 carbon chains Pyrimidines are C and T which have 1 carbon change Gene coding -why you look like you Amino acid coding DNA replication -reproduction -cell reparation Long molecules that store information Base pairing means complementary strands can be replicated Double helix gives bond stability Hydrogen bonds allow for easy copying Deoxy ribo nucleic acid DNA is a molecule found inside the nucleus Would up as a chromosome 99% of DNA in humans is the same Structure: Double helix 5 carbon sugar phosphate groups Nitrogen bases C & G are always paired A & T are always paired Purines are G and A which have 2 carbon chains Pyrimidines are C and T which have 1 carbon change Hydrogen bonds Functions: Gene coding -why you look like you Amino acid coding DNA replication -reproduction -cell reparation Sequence of bases act as protein codes Long molecules that store information Base pairing means complementary strands can be replicated Double helix gives bond stability Hydrogen bonds allow for easy copying