Studied by 0 people
Describe why nucleotides can only be added in a 5’ to 3’ direction
DNA polymerase is specific and the 5’ and 3’ ends of nucleotides are different shapes and therefore can only be complementary with the 3’ end of a developing strand
How can drugs prevent DNA replication
By preventing complementary base pairing
What is the purpose of DNA replication
To copy the DNA so two new daughter cells can be produced with full copies of parental DNA
Describe semi-conservative replication
The process where one of the polynucleotide strands from the original DNA is used as a template
Why is semi-conservative replication important
To ensure genetic continuity, replacement and growth of cells
Describe the role of DNA helicase in semi-conservative replication
Breaking hydrogen bonds between base pairs, to unwind the DNA
Describe the role of DNA polymerase in semi-conservative replication
Catalyses condensation reactions to form a new strand
Describe semi-conservative replication
DNA helicase unwinds DNA, original polynucleotide acts as a template for free nucleotides, new nucleotides are joined by DNA polymerase
Who discovered semi-conservative replication
Meselson and Stahl
How did Meselson and Stahl discover semi-conservative replication
With 14N and 15N nitrogen
Why is semi-conservative replication important
To ensure genetic information is passed from one generation to the rest
How did Nitrogen show DNA replication
Combined densities in a N14 and N15 combination
What is a polynucleotide
Half of a double helix strand
What starts the semi-conservative replication process
Unwinding of the double helix
What bonds does DNA polymerase form
Phosphodiester bonds
