Question

What is true about the lagging strand during DNA replication?

Answer 1

There are not only one but two correct option, which are A and B.

DNA polymerases begin their synthesis at many points of initiation. Following the binding of specific proteins, the double helix opens to allow startup.

DNA synthesis begins on RNA / DNA primers consisting of primase and DNA polymerase a. The replication continues in one direction: in this sense one of the two strands of the DNA ("direct" strand) is traversed by the enzyme in the 3 '→ 5' direction, which allows the synthesis of another strand in the direction 5 '→ 3'. The DNA-ligases then provide the link between the different fragments of the new DNA.

The synthesis of the other strand ("delayed" strand) is more complex because the enzyme travels this strand from 5 '→ 3'. The primase and DNA polymerase α synthesize 30 nucleotide primers in front of the replication zone, and the DNA polymerase constructs small DNA fragments in the 5 '→ 3' direction (approximately 200 nucleotides; Okazaki). Ribonucleases destroy the RNA / DNA primers of the previous fragment and the fragments are then linked together by DNA ligase.