Download objective: 1) to describe how the structure of dna allows it to copy itself

DNA Replication
OBJECTIVE:
1) TO DESCRIBE HOW THE STRUCTURE OF
DNA ALLOWS IT TO COPY ITSELF
Replication
A. Process by which DNA
makes an exact copy of itself
B. Results in 2 identical DNA
molecules
Why replication??
 Copies the genetic code
 Allow new cells to have
exactly the same genetic
info as old cells

This is how traits are passed on
How does replication work?
 Enzymes (special proteins) perform the work of
replicating DNA
 http://www.youtube.com/watch?v=hfZ8o9D1tus&feature=
related
 Step 1: Since the “code” is on the inside of the DNA
ladder, the helix must first unwind and unzip using
an enzyme called DNA helicase
 Step 2: An enzyme called DNA polymerase then
matches up complementary DNA nucleotides with
the open ones on each DNA strand
How replication works, cont.
 Step 3: DNA polymerase
then bonds/glues the sugar
and the phosphate to each
other forming a complete
strand of DNA
 Results: Each new DNA
strand contains ½ of the
original strand and ½ new
nucleotides

This is known as
semiconservative because
each strand has half the old
strand.
 Replication occurs at multiple sites along same
DNA strand
Human DNA has about 3 billion base pairs
 Speeds up the process
