Question

Which event marks the beginning of DNA replication?
Formation of replication bubble
Unwinding of DNA helix
Formation of replication fork
@beccaboo333

Answer 1

@1996bmw most appropiate one is B .there are four steps

Step One: Initiating replication.
The binding of initiator proteins to the replication origin start an intricate series of interactions that opens the helix.

Step Two: Unwinding the duplex.
After initiation, “unwinding’ enzymes called helicases bind to and move along one strand, shouldering aside the other strand as they go.

Step Three: Stabilizing the single strands.
The unwound portion of the DNA double helix is stabilized by single-strand binding protein, which binds to the exposed single strands, protecting them from cleavage and preventing them from rewinding.

Step Four: Relieving the torque generated by unwinding.
For replication to proceed at 1000 nucleotides per second, the parental helix ahead of the replication fork must rotate 100 revolutions per second! To relieve the resulting twisting, called torque, enzymes known as topisomerases-or, more informally, gyrases-leave a strand of the helix, allow it to swivel around the intact strand, and then reseal the broken strand.

Source : Answer yahoo

Answer 2

so it is B

Answer 3

yup :D

Answer 4

thank you