Polymerase Chain Reaction
PCR Applications
Gel Electrophoresis
GE: Applications
100
What is the purpose of Polymerase Chain Reaction (PCR)?
To amplify small amounts of DNA outside of the cell.
100
Name one application of Polymerase Chain Reaction
- Diagnosing Covid-19
- Crime scene investigation
100
What is the purpose of Gel Electrophoresis?
To seprate mixtures of DNA, RNA, and protein.
100
What is the main application of Gel Electrophoresis?
Crime scene investigation.
200
When was it developed?
Developed in the 1980s, by Kary Mullis.
200
True of false: Covid-19 is a DNA virus.
False
200
Who developed the method?
A Sewdish biochemist named Arne Tiselius
200
Name 3 things that contain DNA that can be found in a crime scene.
Skin, blood, hair, and saliva.
300
What are the properties of Taq polymerase that makes the PCR process possible?
It does not denature at high temperatures like other enzymes, allowing the DNA sample to be heated for replication.
300
How is an RNA sample collected for Covid-19?
It is collected through a nose or throast swab that has been isloated and purified.
300
Name the different types of Gel Electrophoresis
- DNA separation
- Protein separation
300
What makes crime scene analysis easier with Gel Electrophoresis?
Each individual has a unique banding pattern, as different DNAs have different restriction sites. This makes identifying a culprit much easier.
400
What is the exact tmeperature at which the hydrogen bonds separate between the nitrogenous bases in the DNA sample?
98 degrees celsius
400
Name the difference between Taq polymerase and Reverse Transcriptase.
Taq polymerase builds DNA from DNA templates, however, Reverse Transcriptase builds cDNA from RNA templates.
400
Name one pro and one con of Gel Electrophoresis
Pros:
- Useful in criminal justice
- DNA samples do not degrade over time
- Not invasive/does not hurt
- Gel is easy to use and does not denature the DNA samples
Cons:
- May be invasive in certain cases
- Contamination of crime scene can cause wrongful accusations
- Evidence can be planted in a crime scene
400
Which suspect is responsible?
Mike
500
Outline the process of Polymerase Chain Reaction?
- The DNA sample is heated, and the H-bonds between bases break
- A short primer complementary to the DNA strand will bind to the sample
- Taq polymerase uses the primers as a starting point for DNA replication
- Post replication: DNA strands are heated to the point of separation when the process is complete
- The process repeats, DNA is doubled after each cycle
500
What is the scientific name of the RNA virus that causes Covid-19?
SARS-CoV-2
500
Outline the process of DNA separation
- A semi-solid medium (gel) is oppositly charged (one side negative, one side positive)
- The negative side has small wells that the DNA samples go in
- Since DNA is negatively charged, it would attract and start moving towards the positive side
- Restriction enzymes then cut up the DNA into small, ununiform pieces
- Shorter fragmants of DNA move faster and longer fragmants of DNA move slowers
- The result is a long strip with striped DNA samples
500
What is the limitation with crime scene investigation?
Some evidence can be manipulated or planted to change the narritive of the investigation.
Examples: Hair can be taken away, or the Crime scene could be cleaned.