DNA REPLICATION TAKES PLACE DURING
INTERPHASE OF MITOSIS AND MEIOSIS.
DURING DNA REPLICATION, DNA CONTENT
DOUBLES (OR QUADRUPLES).
DURING DNA REPLICATION, DNA UNWINDS.
EACH ORIGINAL STRAND SERVES AS A
TEMPLATE FOR A NEW STRAND TO BE MADE.
Objective: Outline the general steps to DNA
replication.
http://amaral.chem-eng.northwestern.edu/roger/Images/dna-replication.jpg
STEPS TO DNA REPLICATION
1) THE ENZYME DNA HELICASE WILL UNWIND
THE DOUBLE HELIX OF DNA FORMING A YSHAPED REPLICATION FORK.
2) THE ENZYME DNA POLYMERASE ATTACHES
TO EACH STRAND OF DNA. DNA POLYMERASE
READS THE ORIGINAL DNA STRAND AND
MAKES A NEW STRAND BY ADDING
NUCLEOTIDES THAT MATCH THE ORIGINAL
STRAND’S NITROGEN BASES.
http://www.viewingspace.com/genetics_culture/images_genetics_culture/gc_assign/
dna_replication.gif
3) TWO DNA MOLECULES FORM THAT ARE
IDENTICLE TO THE ORIGINAL DNA MOLECULE.
THE ENZYMES DETACH AND BOTH DNA
MOLECULES RECOIL.
DNA REPAIR
DNA POLYMERASE CAN PROOF READ DURING
REPLICATION. THEY CAN INSERT, CUT OUT, OR
REPLACE A NUCLEOTIDE IN THE PRESENSE OF
AN ERROR/MUTATION.
1
http://oak.cats.ohiou.edu/~ballardh/pbio475/Heredity/DNA-replication.JPG
2