Structure and Replication of DNA (2) PCR Flashcards
What is PCR (Polymerase Chain Reaction)?
It is a technique that is used to amplify and detect DNA sequences in vitro. With the process containing multiple stage conducted at various temperatures.
What is the first stage of PCR?
The DNA is heated to a temperature of 94 degrees Celsius in order to separate the strands by breaking the weak hydrogen bonds that hold the bases together.
What is the second stage of PCR?
The DNA is cooled down from the near 100 degree temperatures to a temperature of 60 to allow the primers (which are complementary to the DNA sections) to attach to the ends of the regions where replication will start.
What is the third stage of PCR?
The primers allow DNA polymerase to start the replication as the temperature increases to 72 degrees (optimum temperature for DNA polymerase) allowing for the mass replication of DNA as the nucleotides are added.
What is PCR used for?
It can be used medically and forensically allowing genes to be identified from tiny samples allowing for the identification of individuals.
What is the medical use for PCR?
A small sample of DNA can be taken and amplified to show an absence or presence of a particular sequence also allowing for a diagnosis of disease status or the risk for a disease.
What are the forensic uses of PCR?
PCR can be used to settle paternity disputes as 50% of DNA is inherited from a parent meaning there will be a certain pattern when their DNA is amplified and compared and it can also be used to identify people from their remains and to secure the releases of innocent people.
