Part 1: Introduction
DNA, the code of our lives, can now be extracted from animal cells and read like a personal ID card. This is a recent breakthrough that has been revolutionizing the scientific community. It's most commonly known as the main identification method in forensics, to find the truth of the locations of certain people at certain times. It has also been used in food identification, to find out if certain meats are actually pure meat of that type, or if something different is mixed in, and if the food is an endangered species. Also with animals, seeing the genetic code of certain species can determine whether the species are related or not. DNA testing has also cleared falsely convicted criminals of charges, and even saved falsely accused people from death row. DNA is also used to identify corpses if their teeth or fingerprints are compromised, or if only parts of the body remain. DNA testing is the light of truth where before there was none.
In this lab, we'll be comparing DNA samples to simulated criminals' DNA to find the perpetrator. This specific method is used in forensics, but slight variations of it apply to all the uses of DNA above.
Part 2: Experiment
For the procedure, we'll have 6 tubes-- 1 of the "crime scene" DNA, and 1 for each of the 5 suspects. We'll add a restriction enzyme to each one to break apart the DNA at very specific places. We'll then put the tubes in a microcentrifuge to make sure the solution is mixed well. Then we'll put the tubes in a waterbath at 37C overnight. The next day, we'll place them in an ice block. Then we'll put the tubes in the microcentrifuge again to collect all the liquid at the bottom of the tube. Then we'll add loading dye to each tube so we can see approximately where the DNA is, and the dye also keeps the DNA sample in the wells of the gel. After putting in the dye we'll mix it in the microcentrifuge again. Then we put one sample in each lane of the agarose gel, which is inside the electrophoresis apparatus, and use a DNA size marker control for the first lane. Then we'll do the electrophoresis process. After that we'll take out the gel and put it in a staining tray, then put DNA stain in the tray (enough to cover the gel.) The next day, we'll look at the gel and record our results.
Part 3: Discussion
We found the perpetrator to be Katie, because the pattern made by her DNA matched the pattern of the crime scene DNA. One possible source of error could have been contamination, crossover of DNA solution in the gel, mislabeling a tube, or hearing another group's results.
Monday, October 25, 2010
Tuesday, October 5, 2010
Biofuels - Making Something Useful Out of Green Waste
Part 1: Introduction
Biofuels have long been a topic of interest, though much more lately as we entered the "green" trend. As global warming becomes apparent, and as the price of gas rises, more and more people are looking to buy alternative cars, and alternative sources of energy to power their appliances. This demand for green technology has scientists scrambling to find an efficient way to recycle energy that won't harm the environment. Biofuels are usually combustible fuels that are made from biomass. They can be made by adding enzymes to plant material to break them down and release the energy stored inside them.
In this lab, we'll be making a biofuel out of cellulose by adding enzymes, and we'll measure how much fuel is made at several time intervals. My hypothesis is that there will be more indication of fuel as time progresses. We'll have tubes of non-enzyme solutions as controls.
Part 2: Experiment
First, we'll get 7 vials, and label each one: Start, End, E1, E2, E3, E4, and E5. We'll put 500 microliters of stop solution into each one. Then we'll label one 15 ml conical tube "Enzyme Reaction" and the other "Control." Next we'll put 2 ml of 1.5 mM substrate into the "Enzyme Reaction" tube, then 1 ml of the same solution into the "Control" tube. Then we'll label two DPTP's, one "E" for Enzyme, and one "C" for Control.
After preparation, the reaction starts. We use the "C" pipet and put 500 microliters of buffer into the Control tube and mix gently, then we'll remove 500 microliters of the solution and put it into the "Start" vial. Then we'll take the "E" pipet and put 1 ml of enzyme into the Enzyme Reaction tube, and gently mix, then start our timer. At several time stops-- 1 min, 2 min, 4 min, 6 min, and 8 min-- we'll remove 500 microliters of the Enzyme Reaction tube and add it to each vial (e.g. at 1 min, 500 microliters into E1. at 2 min, 500 microliters into E2. etc). After these are all done, we'll use the "C" pipet and take out 500 microliters from the Control tube and put it in the "End" vial. Then we'll wash everything out.
The next day, we'll get a mushroom, measure out 1 g of it, put it into a mortar, add 2 ml of extraction buffer, and make mush with the pestle. Then we'll strain out the solid particles and put the juice in a 1.5 ml microcentrifuge tube. We'll put 500 microliters of stop solution into each of 6 vials (now clean). Then we'll label a 15 ml tube as the type of mushroom, and then put 3 ml of substrate into the tube. Next, we'll put 250 microliters of the mushroom juice into the tube of substrate, and start the timer. At the same time intervals as last time, we'll take out 500 microliters of mushroom extract/substrate mixture from the reaction tube and add it to each of only 5 vials. Then we'll add 500 microliters of extraction buffer to vial 6, and then add one drop of mushroom juice to it. Then we'll analyze the results.
Part 3: Discussion
In each tube through the experiment, each one got progressively more yellow in the slightest bit. It was extremely hard to notice. I had thought it would be a more apparent change.
I can't think of any possible sources of error, except for the tubes being possibly not all the way washed out, and the samples not being pure, as we didn't measure out the supply tubes; only the test ones.
Biofuels have long been a topic of interest, though much more lately as we entered the "green" trend. As global warming becomes apparent, and as the price of gas rises, more and more people are looking to buy alternative cars, and alternative sources of energy to power their appliances. This demand for green technology has scientists scrambling to find an efficient way to recycle energy that won't harm the environment. Biofuels are usually combustible fuels that are made from biomass. They can be made by adding enzymes to plant material to break them down and release the energy stored inside them.
In this lab, we'll be making a biofuel out of cellulose by adding enzymes, and we'll measure how much fuel is made at several time intervals. My hypothesis is that there will be more indication of fuel as time progresses. We'll have tubes of non-enzyme solutions as controls.
Part 2: Experiment
First, we'll get 7 vials, and label each one: Start, End, E1, E2, E3, E4, and E5. We'll put 500 microliters of stop solution into each one. Then we'll label one 15 ml conical tube "Enzyme Reaction" and the other "Control." Next we'll put 2 ml of 1.5 mM substrate into the "Enzyme Reaction" tube, then 1 ml of the same solution into the "Control" tube. Then we'll label two DPTP's, one "E" for Enzyme, and one "C" for Control.
After preparation, the reaction starts. We use the "C" pipet and put 500 microliters of buffer into the Control tube and mix gently, then we'll remove 500 microliters of the solution and put it into the "Start" vial. Then we'll take the "E" pipet and put 1 ml of enzyme into the Enzyme Reaction tube, and gently mix, then start our timer. At several time stops-- 1 min, 2 min, 4 min, 6 min, and 8 min-- we'll remove 500 microliters of the Enzyme Reaction tube and add it to each vial (e.g. at 1 min, 500 microliters into E1. at 2 min, 500 microliters into E2. etc). After these are all done, we'll use the "C" pipet and take out 500 microliters from the Control tube and put it in the "End" vial. Then we'll wash everything out.
The next day, we'll get a mushroom, measure out 1 g of it, put it into a mortar, add 2 ml of extraction buffer, and make mush with the pestle. Then we'll strain out the solid particles and put the juice in a 1.5 ml microcentrifuge tube. We'll put 500 microliters of stop solution into each of 6 vials (now clean). Then we'll label a 15 ml tube as the type of mushroom, and then put 3 ml of substrate into the tube. Next, we'll put 250 microliters of the mushroom juice into the tube of substrate, and start the timer. At the same time intervals as last time, we'll take out 500 microliters of mushroom extract/substrate mixture from the reaction tube and add it to each of only 5 vials. Then we'll add 500 microliters of extraction buffer to vial 6, and then add one drop of mushroom juice to it. Then we'll analyze the results.
Part 3: Discussion
In each tube through the experiment, each one got progressively more yellow in the slightest bit. It was extremely hard to notice. I had thought it would be a more apparent change.
I can't think of any possible sources of error, except for the tubes being possibly not all the way washed out, and the samples not being pure, as we didn't measure out the supply tubes; only the test ones.
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