DNA replication is the process of creating two identical copies from one original DNA molecule. DNA is composed of two strands and each strand of the original DNA molecule serves as template for the production of the complementary strand. Cellular proofreading and error-checking mechanisms ensure near perfect DNA replication. In a cell, DNA replication begins at specific locations, or origins of replication, in the genome. Unwinding of DNA at the origin and synthesis of new strands results in replication forks growing bidirectional from the origin. A number of proteins are associated with the replication fork which helps in terms of the initiation and continuation of DNA synthesis. Most prominently, DNA polymerase synthesizes the new DNA by adding complementary nucleotides to the template strand.
See more at: http://www.medical-institution.com/dna-replication-animation/