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Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
Name: _________Class key________
Period: ________________________
Website upload 2015
The Living Environment ’14-‘15
Mr. Murdoch
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Topic 12.2 assignments
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Website upload 2015
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Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Replication of DNA
Topic:
Objective: How are copies of DNA made in a cell?
 __before__ a cell can divide by __mitosis__ or __meiosis__, it
must first make a ___copy___ of its _chromosomes_.
o The DNA in the _chromosomes_ is __copied__ in a
process called DNA _replication_.
o __without__ DNA _replication_ , new __cells__ would
have only ___half___ the ___DNA___ of their parents.
o ___DNA___ is __copied__ during _interphase_ prior to
mitosis and meiosis.
o It is _important_ that the new __copies__ are
__exactly__ like the original molecules.
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Replication of DNA
Topic:
Objective: How are copies of DNA made in a cell?
 DNA _replication_ depends on _specific_ base _pairing_.
o In ___DNA___ replication, the strands _separate_.
o Enzymes use each __strand__ as a _template_ to
_assemble_ the ___new___ strands.
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Copying of DNA Strands
Topic:
Objective: Describe how original DNA molecules are copied.
 _Semiconservative_ replication:
o _parental_ strands of ___DNA___ separate, serve as
_templates_ and __produce__ 2 __molecules__ of DNA
that have one strand of _parental_ DNA ___and___ one
strand of ‘___new___ ’ DNA.
o _matching_ bases __allow__ DNA to be easily
__copied__.
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
Topic:
The Living Environment ’14-‘15
Mr. Murdoch
Separating of DNA
Objective: What separates (unzips) the double-stranded DNA?
 DNA __Helicase__: enzyme responsible for _uncoiling_ the
double helix and _unzipping_ the weak hydrogen bonds
between the ___base___ pairs.
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Replication of DNA
Topic:
Objective: Visualize the overall process of DNA replication.
 __Build__ daughter ___DNA___ strand
o use __original__ parent __strand__ as “_template_ ”
o ___add___ new matching __bases__
o synthesis __enzyme__ = DNA _polymerase_
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Topic: Replicating of DNA strands
Objective: Describe how individual DNA bases are added.
 Adding bases
o only ___add___ nucleotides __to 3’__ end of a
__growing__ DNA __strand__
o need a “__starter__ ” nucleotide to ___bond___ to
o __strand__ only grows __5’ to 3’__
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Topic: Leading & Lagging strands
Objective: Describe how both separated DNA strands grow.
 __Leading__ strand - _elongates_ as DNA __unwinds__
 __lagging__ strand - _elongates_ in _opposite_ direction.
o _synthesized_ discontinuously into __small__ segments
called Okazaki __fragments__.
o DNA __ligase__ (enzyme) __links__ these sections.
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
The Living Environment ’14-‘15
Mr. Murdoch
Topic: New copies of DNA
Objective: Describe how completed copies of DNA were made.
 New __copies__ of DNA
o Get 2 __exact__ copies of ___DNA___ to split
__between__ reproduced __cells__.
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
Name: ________________
The Living Environment ’14-‘15
Mr. Murdoch
Period: ____________________
Carefully remove this sheet from your packet to hand in.
Work silently and alone to complete this graded exercise.
Check for Understanding
1. What DNA would a reproduced cell contain without DNA
replication?
2. A template is used to create copied DNA. Where does the
cell get the template?
3. Four different enzymes are used for DNA replication. Choose
one and describe how it works.
4. Describe the process of adding nucleotides to both the 3’ and
5’ ends of a DNA strand.
Website upload 2015
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
Page intentionally blank
Website upload 2015
The Living Environment ’14-‘15
Mr. Murdoch
Unit 3 Genetics – Unit 12 Molecular Genetics: (12.2) Replication of DNA-class key
Notes page:
Website upload 2015
The Living Environment ’14-‘15
Mr. Murdoch