DNA Replication Notes

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DNA Replication Notes
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Why must DNA replicate?

• Cells will divide to make more cells and there
  must be a full copy of DNA in each cell
• Before a cell can divide into 2 cells, DNA will
  make a complete copy of itself
• Each cell must have a full copy of DNA, not just
  part

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Why must DNA replicate?
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Definition of Replication

• Replication is the copying of DNA

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Steps of Replication

• Step 1
• DNA must unwind and unzip.
• The weak Hydrogen bonds that hold the DNA strand
  together in the middle are broken by an enzyme.

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Steps of Replication

• Step 1 (Picture)
• A - T
• T - A
• C - G Enzyme unzips
• G C DNA at the
• A T WEAK
• G C hydrogen bonds
• G C

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Steps of Replication

• Step 2
• The DNA strand pulls apart and free DNA
  nucleotides (that are floating around in the
  nucleus) begin to pair up with their
  complementary nucleotide on the parent strand
  with the help of an enzyme.

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Steps of Replication

• Step 2 (Picture)
• A - T T Free DNA
• T A A nucleotides
• C G G floating in
• G C C the nucleus
• A A - T
• G G C
• G G - C

G
A
C
T
G
G
A
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Steps of Replication

• Step 3
• The free nucleotides continue to pair up until
  the entire double strand of DNA has been copied.
• End result 2 complete sets of DNA are made one
  for each of the 2 new cells being made.

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Steps of Replication

• Step 3 (Picture)
• A - T A T
• T A T - A 2 identical
• C G C - G strands of
• G C G C DNA
• A - T A - T
• G - C G C
• G - C G C
• parent new new parent

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DNA Replication Animations

• http//www.stolaf.edu/people/giannini/flashanimat/
  molgenetics/dna-rna2.swf
• http//highered.mcgraw-hill.com/sites/0072437316/s
  tudent_view0/chapter14/animations.html (click on
  how nucleotides are added)

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DNA Replication Simulation

• Make sure Biological Simulations CD is in the
  drive

DNA Replication in real time.