Download DNA REPLICATION Replication: The process of copying DNA prior

Name __________________________________
DNA REPLICATION
Period _______ Date ___________ Seat _____
Replication: The process of copying DNA prior to cell
division
DNA Polymerase:
Helicase: The enzyme that “unzips” DNA by breaking hydrogen
bond between the bases.
The principal enzyme involved in
DNA replication
TEM 60,000x Human DNA
Two
replication
forks
Nucleotides in waiting
New
strands
Replication bubble
Direction of
replication
Direction of
replication
Replication
fork
Original
strand
Original
strand
Helicase
Fun Fact: DNA
polymerase
Fun Fact: Helicase spins
at a rate of 166 times
per second
11
Fun Facts:
Polymerase in E. coli bacteria can synthesize
DNA at a rate of 1000 nucleotides per second.
Scaling this up, the speed of polymerase would
be equivalent to 375 miles per hour.
Polymerase in humans works at a much slower
rate—around 50 nucleotides per second.
Because eukaryote DNA has multiple
replication sites (bubbles), copying the entire
genome only takes the cell about an hour.
Polymerase is very efficient, making on
average one mistake for every 10 million
nucleotides it assembles.
Name __________________________________
DNA REPLICATION
Period _______ Date ___________ Seat _____
Replication in prokaryotes:
Replication in eukaryotes:
Replication begins at one point and goes in two
directions until the entire DNA ring is copied.
Replication happens at many starting points on
chromosomes. Replication ends when all the
chromosomes are copied.
Origins of replication for
Original strands three different replicons
Single origin
Original strands
New strands
Replication proceeds
in both directions
Replication forks
Replication bubbles
New strands
Two replicons on
left fuse together
Replication forks
Termination
of replication
Replicons fuse
Two identical
chromosomes
2
0.25μm
Multiple replication
bubbles 50 to 300
kilobases in length.