DNA Replication : dna_replication_edit1

Where and When does replication occur?

Where - If in the Eukaryotic Cell, it occurs in in the nucleus

When - Before the cell divides, so the offspring also gets a copy
-before mitosis or meiosis (interphase)

Key Players

DNA Polymerase - replicates and builds new DNA strand

Steps of Replication

Helicase - unwinds DNA helix and breaks hydrogen bonds

Primase - lets polymerase know where to start

Ligase - binds bases together that polymerase matched up

Starting Point of Replication Starting on the DNA Molecule

Starts at the Origin

Identified by certain DNA sequences

SSB Proteins (single stranded binded proteins)

Job - bind to the DNA strands to keep them separated

Direction DNA Polymerase Builds

  1. Helicase first unwinds the DNA
  1. Primase makes RNA primers on both strands
  1. DNA Polymerase builds the new strand in 5' to 3' direction
  1. Ligase takes care of the gaps in between the Okazaki fragments, sealing them together

4 Bases in a DNA Molecule

4 bases (A and T) (C and G)

Adenine

Thymine

Cytosine

Guanine

-Builds new strand in the 5' to 3' direction

Leading and Lagging Strands

Leading Strand - built in 5' to 3' direction

Lagging Strand - built in 3' to 5' direction

Primers have to keep being paced in order for DNA Polymerase build

Mistake in Replication

If DNA Polymerase matches the wrong DNA bases, then there could be an incorrectly coded gene

This could end up in an incorrect protein or no protein.

DNA Polymerase minimizes the amount of errors because of its proofreading ability, so it rarely makes a mistake