Question

When mitosis occurs, the DNA inside the cell's nucleus must replicate. The new cell that is formed has an identical copy of its parent cell's DNA. That means it has the same information coded in its genes. During DNA replication, how is an accurate new copy of DNA formed?

DNA polymerases add nucleotides to the exposed base pairs according to base-pairing rules.

During DNA replication uracil bases hold the place of all thymine bases until the newly formed double helix is able to form hydrogen bonds.

DNA helicases add nucleotides to the exposed bases and ensure the formation of hydrog

Answer 1

dna replication is not error proof....polymerase adds nucleotides but it can make a mistake..there are various checkpoints in d cell cycle which ensure that mutated DNA is not passed on further....repair mechanisms work if there is some error...and if there is major error then the cell is stopped from moving into the mitotic phase...

Answer 2

So which one is it? .-.

Answer 3

i think its A....

Answer 4

thanks! got it!

Answer 5

@LollipopTARDIS @shrutipande9 The check points do not typically stop things before replication finishes. It is A, but the checkpoints mentioned have little to do with the copying of nucleotides and the semi-conservative nature of replication. The polymerases themselves do most of the correcting but have a limited capacity to do so. In general any mutation that is neutral with respect to fitness and is not corrected via the polymerases, will be maintained in the daughter cell(s) and pass on.