BME100 f2013:W1200 Group14 L4
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Lab Write-Up 1 | Lab Write-Up 2 | Lab Write-Up 3
Lab Write-Up 4 | Lab Write-Up 5 | Lab Write-Up 6
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LAB 1 WRITE-UP
Initial Machine Testing
The Original Design
Experimenting With the Connections
When we unplugged the LCD screen (part 3) from the circuit board(part 6), the display screen turns off and shows nothing at all.
When we unplugged the white wire that connects the circuit board(part 6) to the heating plate(part 2), the temperature sensor malfunctions and displays the incorrect temperature on the LCD screen.
The test was run on Wednesday, October 23rd, 2013 at 1:08 PM.
DNA Sample Set-up
Research and Development
PCR - The Underlying Technology
Components of PCR:
PCR, or polymerase chain reaction, is used to amplify DNA to diagnose disease, map the human genome, or even to solve crimes. There are several components involved in completing PCR-- the template DNA, the primers, the Taq polymerase, magnesium chloride, and deoxyribonucleotides. Through a process of heating and cooling, the DNA is rapidly amplified. Usually, there is a target sequence within the template DNA that needs to be amplified-- through the heating and cooling process, the target sequence is amplified. The purpose of each component is as follows:
Template DNA: The template DNA contains the target sequence, and is the basis for the amplification. Without the template, the target sequence cannot be amplified, and the primers have nothing to bind to, and polymerase has nothing to copy.
Primers: The primers bind to each single-stranded DNA and functions almost as a signal for Taq polymerase to begin the construction of the complementary sequence. Furthermore, the presence of both forward and reverse primers ensures that the target sequence, in particular, will be amplified, because the primers are made specifically for the sections of the template DNA which include the target sequence.
Taq polymerase: This is an enzyme which constructs the complimentary sequence to the single strands of the template DNA.
Magnesium chloride: The magnesium chloride acts as a catylyst for the polymerase reaction, and helps the reaction move along faster.
Deoxyribonucleotides: These are free-floating nucleotides, and these are the bases that are used by Taq polymerase to create the complimentary sequence for the single-stranded DNA. These nucleotides are adenine, guanine, thymine and cytosine. Adenine is paired with thymine, cytosine with guanine.
The aforementioned materials are the key components in a PCR reaction. The first step of PCR is to heat the DNA to around 95 degrees celsius for around 3 minutes, and this allows the DNA to denature and unwind into two separate strands. The temperature, which is near boiling, and the required time, are both imperative to this reaction because this is the amount of energy that is required to break the hydrogen bonds between the nucleotides of the complementary strands. Once the DNA denatures, the temperature must be lowered to 57 degrees for around 30 seconds. The lowering of temperature allows for the forward and reverse primers to bind onto each single stranded-DNA. After 30 seconds of this, the temperature is once again re-heated to 72 degrees, the ideal temperature for Taq polymerase. Taq polymerase now begins constructing complementary strands to each single template strand. This continues for around 3 minutes. This cycle repeats itself over and over, until the "target sequence" is amplified more so than the original template DNA. The strands are complementary, and are created with paired nucleotides-- adenine binds with thymine, and cytosine with guanine. Base pairing, which is done through hydrogen bonds, are what create the "spiral staircase" of DNA structure. This is also what allows primers to the template strand.