U1:KA2 - Replication of DNA Flashcards
What does PCR stand for?
Polymerase chain reaction
What is PCR used for?
To produce more copies of DNA ‘in vitro’
What does PCR do?
It amplifies DNA using complementary primers for scientific target sequences
What are primers?
They are short sections of nucleotides which are complementary to specific target sequences at the 2 ends of the DNA region to be amplified
How does PCR amplify DNA?
By using repeated cycles of heating and cooling
What is the first stage of PCR?
DNA is heated to 92-98 degrees to separate the strands
What is the second stage of PCR?
DNA is cooled to 50-65 degrees to allow primers to bind to target sequences
What is the third stage of PCR?
DNA is heated to 70-80 degrees for heat tolerant DNA polymerase to replicate region of DNA
What are the three practical applications of PCR?
Solving crimes in forensics, settle paternity suits and diagnose genetic disorders
What is the first stage of the replication of DNA?
To begin DNA replication, DNA is unwound and hydrogen bonds between bases are broken to form two template strands
What is the second stage of the replication of DNA?
The primer binds to the 3’ end of the template DNA strand allowing DNA polymerase to add DNA nucleotides
What is the third stage of the replication of DNA?
DNA polymerase adds DNA nucleotides, using complementary base pairing, to the deoxyribose (3’) end of the primer this allows the new DNA strand to form.
What strand is replicated continuously in DNA replication?
The leading strand is replicated continuously
What strand is replicated in fragments?
The lagging strand is replicated in fragments
What enzymes seals the fragments together?
DNA ligase
