Science

Hi again Gaurav,
Let me explain you Initiation first:
(a) Initiation:
In a cell, DNA replication begins at specific locations in the genome, called origins. In case of E. coli the origin of replication is a sequence of approximately 245 base pairs (bp) called oriC. Origins contain DNA sequences recognized by replication initiator proteins (e.g. DnaA in E. coli and the Origin Recognition Complex in yeast), these proteins bind to start the process of replication. The initiator proteins recruit other proteins to separate the two strands and initiate replication forks.
Unwinding of DNA at the origin, and synthesis of new strands, forms a replication fork. The replication fork is a structure which forms when DNA is being replicated. It is created through the action of helicase, which breaks the hydrogen bonds holding the two DNA strands together. The resulting structure has two branching prongs, each one made up of a single strand of DNA.
Now, Elongation:
Once replication has been initiated; the replication forks progress along the DNA and participate in the synthesis of new strand. At the chemical level, the template dependent synthesis of DNA is very similar to the template-dependent synthesis of RNA that occurs during transcription, but the two processes are quite different.
Due to lack of Image and graphic supplies, I lack in showing you the diagrams. But, I hope this was helpful enough.
All the best.