What is the basis for the difference in how the leading and lagging strands of DNADNA molecules are synthesized?

The origins of replication occur only at the $55$ end.Helicases and single$-$strand binding proteins work at the $55$ end.DNADNA polymerase can join new nucleotides only to the $33$ end of a pre$-$existing strand, and the strands are antiparallel.DNADNA ligase works only in the $3535$ direction.