CSI 94549 Who killed Kenny?

Intro

Today DNA profiling does not only use fingerprints but any part of the suspect with DNA in it. Restriction enzymes are used to cut fragments of the DNa at specific sites and the resulting strands carry different lengths. DNA profilers can then use agorose gel electrophoresis. This process seperates DNA fragments by size by adding a blue color which attracts to the shorter strands and a cyan color that attracts to the longer strands. The lectrophoresis places DNA through a gelatin and has a direct current pass between wire electrodes. The DNA fragments are negatively charged and therefore are attracted to the other side or positive pole. Smaller DNA fragments can move easier through the gel and get farther. Based on the length of the strand a persons DNA pattern can be obtained. Humans can be up to 99.9 % identical DNA but that difference can still be huge. It is not likely to find two people with very similar DNA sequences in the same place. DNA testing is used to identify remains of soldiers killed in combat and currently frees 1/3rd of all sexual assault suspects. DNA testing can alos be used to identify different versions of the same disease. It can also determine whether a bone marrow transplant takes place and can show the relatedness of animals.

 DNA profiling was first discovered by Alec Jeffrey in 1984. DNA profiling is an encrypted set of numbers that reflects a persons genetic makeup. A buccal swab is used to pick up the DNA and avoid cross contamination. DNA can be picked up by anything, blood, semen, and other fluids/ tissues. Todays profiling is based on the number of repeat bases or short tandem repeats.

 Procedure

In this CSI lab 5 suspects will be taken and one will be the theoretical killer of a student. There DNA will be taken and using enzymes taken from ecoli they will cut the DNA into different sized strands. This will happen within an incubator for 45 minutes at 37 degrees Celsius the temperature that the ecoli generally lives at in the small intestine. After the incubation we shall add loading dye to the tubes of DNA. We will place the agarose gel in the the electrophoresis apparatus. The shorter strands in will reach closer to the positive end and visa versa. After 30 minutes the strands will be removed and dyed by either cyan for the shorter strands and blue for the longer strands. Based on the pattern of the DNA we will match it to the murderer.

Biofueling Future Generations

Introduction

 Backround: In this lab we are exploring the world of creating biofuels from plants. The process uses enzyymes and bacteria to create a finished product. Enzymes are proteins that speed up chemical reactions without actually being consumed. Increasing temperature can speed up reactions but if enzymes are neccessary the temperature has to be at a specific range to be effective. Most enzymes function at a range between 20-40 degrees Celsius.In this lab we are taking the sugars found within cellulose within the cell wall of plants. In this reaction cellulases will break down the cellulose into strands of glucose. Ethanol was the first type of biofuel to be created but because of its low yield of energy, scientists have begun to search for more effective solutions. Our lab is a miniature version of this research and in order to make sure detect that our lab was successful in creating glucose we are adding a seperate substrate called p-nitrophenol which when added to a basic solution, will cause the solution to turn yellow. On the second day of this lab we will dealing with mushrooms that are naturally decomposers, which should break down the cellulose just as effective. Today most gas stations contain 10 percent ethanol within the regular gasoline.

Hypothesis: I believe that adding mushrooms on day two  will speed up the reaction because mushrooms are naturally decomposers and therefore will do their job effectively and increase the reaction rate.

Procedure: In this lab we are taking cellulose from plants and introducing an enzyme called cellobiose which creates two glucose molecules bonded together. If we wanted to make ethanol we would then add cellubiase which would break the molecule into two glucose which we would then create into fuel and burning the fuel would create energy. Instead we are adding an alternative substrate which will make a glucose molecule and Pnitrophenol. The addition of a strong base will begin to turn the solution yellow and throughout the reaction we will add some of the solution to a number of vials.

Results: In the lab adding enzymes to our substrates did not change anything on the macroscopic level. Only when the base was added did the product turn yellow. On day two the mushrooms extract did the exact same thing and therefore should contain similar enzymes for breaking down the cellubiose. Some possible sources of error could have been, leftover products from the class before us, changing the rate of reaction slightly, or different conditions from day one to day 2.