The Three Dramatic scenes of Replication

Replication is a critical stage;  chromosomes must replicate before they can undergo mitosis. This stage can be split into three parts ('scenes'): initiation, elongation, and termination. 

INITIATION: 
Main 'characters':

• Helicase
• Gyrase

-Helicase is an enzyme that initiates the process of replication
-This enzyme unwinds the two strands of parent DNA and breaks the hydrogen bonds between the complementary base pairs
-Gyrase is an enzyme responsible for releasing the tension between the strands of DNA
-Gyrase cuts the ends and reattaches the strands

ELONGATION:
Main 'characters':

• Primase
• Polyermase 3

-Primase is an enzyme that provides RNA primers
-RNA primers are the starting blocks for new DNA growth
-Primers connect to complementary nucleotides
-Leading strands only require 1 primer, but there are many primers for the discontinuous lagging strands
-Polymerase 3 is an enzyme that combines monomers and acts as the photocopier
-When new DNA grows, it grows in the direction of 5' to 3'
-Elongation of the leading strand is smooth because it is continuous


TERMINATION
Main 'characters':

• Ligase
• Polymerase 1

-In termination, polymerase 1 (who is responsible for proofreading/checking for mistakes made by polymerase 3) replaces RNA primer with DNA components
-Ligase then bonds the Okazaki fragments (the lagging strands) to the growing strand