Part 1 Climate Change and Corresponding Efforts in China. Many observations in recent 100 years show that the earthâs climate is now. experiencing significant change characterized by global warming. And the trend of. climate change in China is generally consistent with that of global climate change.
Primase synthesizes the RNA primer that is used to start an Okazaki fragment on the lagging strand. DNA polymerase III continues to add nucleotides to the leading strand right at the replication fork. DNA polymerase I (not at the replication fork) replaces the RNA primers with DNA nucleotides. DNA ligase, also not at the replication fork fuses the new nucleotides produced by polymerase I with the adjacent strand. Replication continues until there are two completely seperate DNA strands that are identical.
Copying occurs at a localized region called the replication fork, which is a Y shaped structure where new DNA strands are synthesised by a multi-enzyme complex. Here the DNA to be copied enters the complex from the left.One new strand is leaving at the top of frame and the other new strand is leaving at bottom.The first step in DNA replication is the separation of the two strands by an enzyme called helicase.he other half of the DNA double helix, known as the lagging strand, has the opposite 3' to 5' orientation and consequently requires a more complicated copying mechanism. As it emerges from the helicase, the lagging strand is organised into sections called Okazaki fragments.