DNA Replication - Animation 3D

DNA Replication
iNTRODUCTION

DNA replication is an intricate process requiring the concerted action of many different proteins. The replication proteins are clustered together in particular locations in the cell and may therefore be regarded as a small “Replication Factory” that manufactures DNA copies. The DNA to be copied is fed through the factory, much as a reel of film is fed through a movie projector. The incoming DNA double helix is split into two single strands and each original single strand becomes half of a new DNA double helix. Because each resulting DNA double helix retains one strand of the original DNA, DNA replication is said to be semi-conservative.

DNA REPLICATION PROTEINS

1- DNA replication requires a variety of proteins. Each protein performs a specific function in the production of the new DNA strands.
2- Helicase, made of six proteins arranged in a ring shape, unwinds the DNA double helix into two individual strands.
3- Single-strand binding proteins, or SSBs, are tetramers that coat the single-stranded DNA. This prevents the DNA strands from reannealing to form double-stranded DNA.
4-Primase is an RNA polymerase that synthesizes the short RNA primers needed to start the strand replication process.
5-DNA polymerase is a hand-shaped enzyme that strings nucleotides together to form a DNA strand.
6- The sliding clamp is an accessory protein that helps hold the DNA polymerase onto the DNA strand during replication.
7-- RNAse H removes the RNA primers that previously began the DNA strand synthesis.
8- DNA ligase links short stretches of DNA together to create one long continuous DNA strand.