Answer: DNA is a molecule made up of two strands, twisted around each other in a double helix shape. The two strands are complementary which have a 5 prime end and a 3 prime end. To understand this question you must first understand the steps that follow.
DNA Replication:
Step one:
DNA Helicase (unzips) separates the strands.
Step two:
DNA Primase starts the process and makes a small piece of RNA called a primer. This marks the starting point for the DNA.
Step three:
DNA Polymerase binds to the primer and will make the new strand of DNA. DNA Polymerase can only add DNA bases in one direction, from the 5 prime end to the 3 prime end.
Step four:
Once the new DNA is complete the enzyme exonuclease removes all the RNA primers from both strands of DNA.
Step five:
Another DNA Polymerase fills in the gaps that are left behind with DNA.
Step six:
DNA Ligase seals up the fragments in DNA, in both strands to make a continuous double strand.
Final answer:
DNA Replication cannot replicate at the same time due to the leading and lagging strand.
Good luck!