CSI:AHS (DNA Profiling)

Intoduction: (a) Restriction enzymes, which come from bacteria, are used in DNA profiling. These enzymes work best under specific buffer and temperature conditions. They act like scissors and cut the DNA according to its recognition of sequences and base pairs. This happens on a restriction site which is what biologists look at to help them identify someones DNA. The DNA that is seperated and observed is done through the process agarose gel electrophoresis. This process organizes the DNA fragments by size and put on and agarose gel slab and then has an electric current pass between the elctrodes. By having this done, the fragments of DNA will be drawn to the positive pole which will allow all the fragments of the same size to form into bands which is seen after the DNA is stained. To compare DNA of different individuals to others, radioactive probes are needed. They recognize and pull together the specific sequences of nucleotides. Evidence for DNA fingerprinting is easily obtained through any material that might contain DNA. Population genetics and genetic statistics are two factors that can possibly aggect the relability of DNA profiling. DNA profiling is used in many other ways besides forensics. Some of the other researches DNA profiling is used for are food identification, the identification of human remains, paternity testing, and the identification of human remains.
(b)The objective of this lab is to identify the criminal by using DNA profiling. We will use the DNA of five suspects to see which of them did the crime. We will be able to observe the DNA fragments and match it up the DNA from the crime scene.
(c)The restriction enzymes will cut the DNA at its palindromes. Then the different lengthed fragments of DNA will be generated which will be the DNA fingerprint. Then we will run a gel and stain the DNA to figure out and observe the DNA and match it up to the crime scene DNA.
(d) In lane 1, the DNA size marker is a control for electrophoresis and will show if this process worked or not.
Results: Once the gel was stained overnight and drained, it showed that lane 5 and lane 2 matched. Lane 2 is the crime scene DNA and lane 5 is suspect 3's DNA.
Discussion: (a) Because of the results, out of the five suspects, katie is the criminal. Her DNA matches the DNA found at the crime scene.
(b)A possible error could have been that when pipeting the different DNA's into the lanes, we could have been careless to put them into the right lane which could lead to the identification of the wrong suspect.

Biofuels

Inroduction:
(a) When biofuels are made, a source that was currently living is turned into reusable energy as fuels. This is different from fossil fuels because the materials used to make them are dead rather than living. The four main types of biofuel development are cellulosic ethanol(cellulose to glucose),ethanol production from sugar and starch sources,syngases(from biomass burning),and biodiesels(from oils). Right now in the fuel industry,the ethanol produced comes from starches that is turned into sugar. There are two problems(a lot of the plant ends up being unused, and is a food source) with this method so researchers are trying to find out how to produce ethanol as fuels by using cellulose instead of using starches. Enzymes lower the activation energy of a chemical reaction which allows it to occur at a much faster rate. Biofuel industries use cellulases(family of enzymes) from cellulose to turn it itno sugars(glucose). It can then be made into ethanol by means of fermentation. The ethanol produced can then be used to power certain engines and combined wtih gasoline to power vehicles.
(b) The purpose of this lab is to identify the reaction rates with and without the prescense of an enzyme. The practical use of this enzyme will prove relevent since the biofuel industry is using enzymes to convert into ethanol.
(c) We will use 5 cuvettes and fill them equally with solution. The chemical reaction will begin when the buffer is added to the controlled solution. The stop solution (enzyme reaction) will kill the cellobiase and turn P-Nitophenal yellow.
(d) I predict that the stop solution will turn the liquid inside the cuvettes more and more yellow. But on the second day of the lab where the mushroom is added, it will be a consistent color of yellow throughout all of the cuvettes.

Results/Obsevations:
On the first day of the lab, when the stop solutions were added to each of the cuvettes, the color of the solution in them became noticably more yellow each time. On the second day with the addition of an enzyme to speed up the chemical reaction, each solution in the cuvettes remained unchanged. All were the same shade of yellow.

Dicussion:
(a) The first day of the lab consisted of different shades of yellow of solution as time went on. This was the progress of an uninfluenced chemical reaction. The second day of the lab consisted of an unchanging shade of yellow solution as time went on. With the addition of an enzyme (mushroom), the chemical reaction occured and finished much quicker.
(b) Some errors for this lab could be that the time sensitive steps were not done properly-did not count the minutes for the addition of stop solution to the cuvettes.

Yogurt Lab Discussion

a) In the first test tube, which was the negative control containing only milk, remained unchanged. In the second test tube, which was the positive control containing milk and yogurt, the texture appeared more like a thick liquid resembling yogurt. It also smelled like yogurt, and so I conclude that the bacteria from the added yogurt affected the milk and turned the whole mixture into yogurt. In the third test tube, which contained the ampicillin and yogurt, the state of the mixture was liquid and smelled like milk. Since the ampicillin is an antibiotic, it must have fought off the bacteria from the yogurt and enabled it to turn into milk. The last test tube contained yogurt and E.coli. This would answer the question as to see if any type of bacteria would be able to produce yogurt. The texture was somewhat resembling to yogurt but the smell was anything but. E.coli is unable to produce yogurt.
b)One possible error that could have occurred could be that the vortex was not properly used and the mixtures in the test tubes were not fully mixed causing complications that would later affect the results.

Yogurt

a) Bacteria-a terrifying species or an essential part of every day life? The answer is both! They are both potentially harmful and a life necessity. Bacteria are everywhere, but are typically too small to be seen by the naked eye. They are prokaryotes which means they are single celled with cell walls. There are many different shapes of bacteria. The three most common shapes are coccus,bacillus, and spirillum. Like all other life forms, bacteria require food(usually sugars). Bacteria uses enzymes to chemically ingest and break down the sugars into their molecules. Bacteria are crucial when it comes to making certain food products like yogurt. Yogurt can be produced when a specific kind of bacterica is added to milk. The mixture then begins to ferment . The bacteria takes in sugars from the milk and releases lactic acid.
b) The objective of this lab is to use a model to utilize Koch's postulates which involves making yogurt. This lab will be a controlled experiment using microbial techniques.
c) There will be four test tubes all containing milk. One of the tubes will have nothing added to it, therefore containing only plain milk. The other tubes will have yogurt, yogurt + ampicillin, and E.coli added to them. After inoculating the milk with the yogurt, we will need to check that the culture is the same.
d) The controls will be tube 1(milk) and tube 2(yogurt). Tube 1 is negative and tube 2 is positive which will verify the results of the lab.