DNA Replication Flashcards
Describe DNA replication x7
Enzyme DNA helicase attaches onto DNA molecule
This causes the complementary bases paid to break
Two polynucleotide strands separate
Free (activated) nucleotides line up with complementary base pairs
The nucleotides are only held in place by hydrogen bonds between complementary base pairs (no phosphodiester bonds)
Second enzyme attaches DNA polymerase
Catalyses the formation of phosphodiester bonds between activated nucleotides
Difference between normal nucleotides and free nucleotides
(+name)
Activated nucleotides
Contains three phosphate groups (normally only one)
What does DNA polymerase do
Moves down the molecule and catalyses the formation of a phosphodiester bond between the activated nucleotides
What type of reaction does DNA polymerase do + when
Condensation reaction
When it catalyses reaction between adjacent nucleotides
Where does the energy for the DNA polymerase condensation reaction come from
When the two extra phosphate groups leave
What is semi-conservative replication
When there are two copies of a double stranded DNA molecule but each molecule contains one strand from the original DNA molecule and one strand which is brand new.
What is semi-conservative replication
When 2 new strands of DNA are formed
1 strands contains all the originals DNA
And the 2nd contains none of the original DNA
What is the role of DNA polymerase in DNA replication
Joins nucleotides
Why does DNA polymerase work in opposite directions
1 strands anti parallel
The shape of the nucleotides is different
Enzyme/ DNA polymerase have active site with specific shape
Only binds with the 3’ end