DNA replication Flashcards
How is DNA replicated in humans
Semi-conservatively
4 requirements of semi conservative replication
1) four types of nucleotides (A,T,G,C)
2)both strands of DNA molecule acting as a template for the attachment of nucleotides.
3)the enzymes DNA polymerase and DNA helicase
4)source of chemical energy to drive the process
Process of DNA rep
1)DNA helicase breaks the hydrogen bonds between bases. This allows the double helix to unwind. The two strands act as template
2)Free floating DNA nucleotides attracted to exposed bases via complementary base pairing. they then form hydrogen bonds
3)DNA polymerase joins adjacent nucleotides on new strands by condensation recation,forming phosphodiester bonds
Why is the replication called semi conservative
Each new strand formed contains one original and one new strand
Importance of enzymes in DNA replication
DNA helicase is needed in order to break hydrogen bonds in order to unwind DNA . Without helicase it would be quite difficult to break hydrogen bonds between complementary bases without damaging the DNA .
DNA polymerase is needed in order to join adjacent nucleotides together and form a phosphodiester bond. This important for the structure of DNA as it allows to form the sugar phosphate backbone which provides protection for bases.
If these enzymes did not exists DNA would not be able to replicate and this has knock on effect for mitosis as in s-phase the DNA is required to undergo DNA replication in order that mitosis can function efficiently to form identical daughter cells. Without this We wouldn’t be able to grow new cells or repair damaged cells. Can link Red blood cells and clonal expansion to form plasma cells to fight of infections
