tell me detail about dna biosynthesis?

Answer 1

What PIPI B has written is OK except that it missed a vital point. It is the DNA polymerase that polymerises the deoxyribonuleotides into long chain of DNA.
Secondly, the ligase joins the okazaki fragments.
Thirdly, the polymerization is an energy dependent process.
Fourthly, DNA replication is bidirectional.
Fifthly, the units are nucleotide triphosphates.

Answer 2

Simple summary of DNA replication:

1) Topoisomerase "topples" the balance of the DNA by changing the charge of the DNA.
2) Helicase unwinds the double-stranded DNA.
3a) Leading strand: RNA polymerase III attaches on the 3'OH end
4a) dNTPs alligns and RNA polymerase III elongates.
3b) Lagging strand: Primers are attached to the lagging strand to provide a new 3'OH end.
4b) RNA polymerase III then elongates along with alligned dNTP.
5b) Stops at each primer and move on to the next one
6b) Between primers are called okazaki fragments
7b) RNA polymerase I removes the primer and joins the DNA up.

Answer 3

There are lots of sites out there that explain DNA replication in considerable detail, and I see no reason to repeat them. Try one of these sites:
http://en.wikipedia.org/wiki/DNA_replication
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/D/DNAReplication.html
http://www.contexo.info/DNA_Basics/DNA%20Replication.htm
http://www.emunix.emich.edu/~rwinning/genetics/replic3.htm
http://www.elmhurst.edu/~chm/vchembook/582dnarep.html
http://web.indstate.edu/thcme/mwking/dna.html