DNA replication 1.2 Flashcards
Why do cells need to copy their DNA?
To ensure than an exact copy of a species’ genetic information is passed on to each new cell.
What type of replication ?
Semi conservative
How do the weak hydrogen bonds break between bases?
ATP
What attaches to the exposed 3’ end of the template strand?
Primer
What is the job of DNA polymerase?
Adds free DNA nucleotides to the 3’ end
On the lagging strand what does the addition of DNA nucleotides create?
fragments
What does the enzyme ligase do?
Joins primers and fragments
What does PCR allow?
It allows tiny fragments of DNA to be amplified in vitro by repeated cycles of heating and cooling.
What are the requirements for PCR?
Primers, DNA nucleotides, DNA sample, Heat tolerant DNA polymerase, buffer solution and thermal cycler
What are the primers in PCR
They are sequence specific designed by the experimenter to match the beginning and the end of target fragments
Why Heat Tolerant DNA polymerase?
The high temperatures would denature normal
Why is buffer solution added to PCR?
To maintain pH
Stage 1 of PCR
All requirements added to PCR tube
Heated between 92-98 degrees Celsius
Denature DNA and separate strands
Stage 2 of PCR
Cooling to between 50-65 degrees Celsius
Allows primers to bind to target sequences
Stage 3 of PCR
Temp raised to between 70-80 degrees Celsius
DNA polymerase adds free DNA nucleotides to 3’ end of newly forming strand.
