Quote of the Day #1

"Science and everyday life cannot and should not be separated." -Rosalind Franklin

The 3 Acts of DNA Replication

Initiation:

• Helicase unwinds and separates DNA (at the point of origin)
• Binding proteins bind to keep the DNA strands apart and unwound
• Gyrase enzyme cuts the DNA to release the tension
• Primase makes an RNA primer which the DNA polymerase III uses to begin replicating the new strands

Elongation:

• Polymerase III adds nucleotides to the 3' of the new strand
• DNA's anti parallel structure results in the new strands growing in opposite directions
• Leading vs Lagging strands:
•  the leading strand replicates continuously
•  the lagging strand replicates discontinuously
•  RNA primase synthesis RNA primer
•  Polymerase III extends the strand by adding new nucleotides to the 3' end
•  a new DNA fragment is generated from the end of each primer
•  the DNA fragments are called Okazaki fragments
•  Polymerase I removes RNA primer and fills the gap by extending the neighbouring DNA
•  Okazaki fragments are joined by DNA Ligase

Termination:

• Newly formed strands rewind
• Replication machine dismantles as the new DNA molecules separate from each other and the DNA replication is complete