What holds DNA strands apart during replication?

Answer 1

What prevents the wrong nucleotide from being added to the new strand during DNA replication?

DNA polymerase 3 and DNA polymerase 1 can become what is known as exonucleases. an exonuclease can go back and "proofread" the replicated DNA and if there is a mistake, then everything beyond that incorrect nucleotide is removed and the DNA polymerase 3 will re-replicate from the bad point on.

the protein p53 holds the cell in the G1 and S phase of replication which allows more time for proof reading the replicated DNA

Answer 2

After DNA is unwound and split by a protein called helicase. Behind the helicase is another protein called single strand binding protein (SSB) which keeps the separated strands from reannealing.

Answer 3

On the leading strand, replication occurs immediately after helicase splits the two strands, so there is not chance for the strands to reattach. On the other strand, the lagging strand, there is a delay of about 1 second (1000 base pairs) before the strand is replicated, which is an extremely long time in biochemical terms. Another protein, known as Single Stranded Binding protein (SSB) in E. coli (it goes by other names in other organisms but does the same job) binds to the single stranded DNA strand to prevent it reannealing with itself. SSB is displaced, when access to the single straded DNA is needed, by a subunit of DNA polymerase.

Answer 4

During DNA replication, an enzyme called DNA helicase is responsible for unwinding the double helix structure of DNA, separating the two strands. Single-strand binding proteins then help to stabilize the separated strands and prevent them from reannealing.

Answer 5

single-stranded binding proteins

Answer 6

single-strand binding proteins