DNA replication Flashcards
(30 cards)
when does DNA replication occur
it occurs within the cell cycle before cell division - happens in interphase of cell cycle to be specific the s phase
why does DNA replication happen
as DNA needs to be replicated to the new cells that are created also have a full copy of DNA
what is the name of the way DNA replicates
semi conservative
what happens in semi conservative replication
In the new cell, in the daughter DNA 1 strand comes from the parent cell so its parental DNA and 1 strand is new DNA
what is each strand of DNA in daughter cell called
1 strand is original and 1 strand is newly synthesised
why is complementary base pairing important in DNA replication
as it allows identical copies of DNA to be created and it helps to reduce copying errors which would result in mutations
what does complementary base pairing reduce the change of in DNA replication
it reduces the chance of copying errors which would result in mutations
what is the name of the 2 enzymes involved in DNA replication
DNA helicase and DNA polymerase
what is the first stage of DNA replication
at the start DNA helices breaks the hydrogen bonds between the complementary base pairs between the 2 antiparallel strands of parental DNA. As DNA helices breaks the hydrogen bonds it causes the double helix to unwind and the 2 strands separate
at the first stage of DNA replication what does DNA helices do
it breaks the bonds between the complementary base pairs
due to the hydrogen bonds being broken in the first stage of DNA replication what is left
the 2 separate strands of parental DNA
what is the 2nd stage of DNA replication
the once the 2 strands are separated each strand will act as a template which allows complementary DNA nucleotides within the nucleus to align opposite their complementary base pairs
what does the 2 strands acting as a template allow in the 2nd stage of DNA replication
the template allows complementary DNA nucleotides within the nucleus to align opposite their complementary base pairs
where are DNA nucleotides found
freely floating in the nucleus
what is the 3rd stage of DNA replication
then the adjacent nucleotides are joined together via a condensation reaction this reaction creates a phosphodiester bond. the DNA polymerase catalyses the adjacent molecules joining together.
in DNA replication what reaction takes place to join adjacent nucleotides together
a condensation reaction which eliminates a water molecule and creates a phosphodiester bond
what bond is created when adjacent nucleotides join together in RNA replication
phosphodiester
what does DNA polymerase do in DNA replication
catalyses the joining together of adjacent molecules
what’s the function of DNA polymerase
join together nucleotides
whats is the final stage of DNA replication
there is now 2 sets of daughter DNA which contains 1 strand of original parental DNA and 1 strand of newly synthesised DNA
what were meshes and stahls 2 hypothesises
DNA must replicate conservatively or semi conservatively
what is semi conservative replication
where from the original DNA when replicated to make 2 lots of DNA 1 strand is from original strand and other is newly synthesised
what is conservative replication
where the original DNA after replication would remain intact and the newly synthesised DNA would combine together, so the original DNA is conserved - there would be one original DNA molecule and one newly synthesised DNA molecule
which replication did meshel and stahls experiment prove
it proved that its semi conservative replication
