DNA Structure

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• DNA Structure
• What is it?
• Bases (AGCT) form the stairs of the ladder, are
  faithfully paired and exhibit differences.
• P
• S-A T-S
• P P
• S-G C-S
• P P
• S-A T-S
• P P
• S-G C-S
• P
•  Sugars (S) and phosphates (P) form the sides of
  the ladder (identical for all DNA).
• Bases (AGCT) form the stairs of the ladder, are
  faithfully paired by hydrogen bonds and exhibit
  differences. A T and G C

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DNA Structure

• Primary genetic material is composed of two
  complementary strands
• Form a double helix or twisted ladder
• Sides are sugar phosphate and the steps are base
  pairs
• Four Bases- 2 Purines Adenine and Guanine and 2
  Pyrimidines- Cytosine and Thymine
• Asian Guys are Pure!

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DNA StructureNucleotides are the building
blocks themselves composed of PBS
Nucleotides-PBS Phosphate (negative charge)
Base (AGCT-Asian Guys Can Teach) Sugar
(deoxyribose-5C) Phosphate-Sugars Connected by
phosphodiester linkages
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Basic Components of Nucleic Acids
5end Phosphate SugarBase Phosp
hate SugarBase 3end
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DNA Structure2 Complimentary, Antiparallel
Strands held together by Base Pairs- H Bonds
.
AT held with 2 H Bonds
GC held with 3 H Bonds
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Wheres Daddy?
PCR product size (bp)
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Father
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Child 1
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Child 2
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Child 3
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Mother
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DNA St. Patricks Day Salute to the Molecule of
HeredityFrom Biology 110- UNC 1993 Steve Lee

• The molecular structure today
• Is hereditys DNA
• With nucleotides
• completely comprised
• of a sugar and phosphate and base
• The bases you see are so keen
• They include thymine and adenine
• Cytosine and one more
• with guanine can store
• all the info with rungs in between
• The sides of the ladder you know,
• are sugar and phosphate which show
• that Franklin was right
• double helix is tight
• ten base pairs per turn in a row

Adenine and thymine can base pair Forming two
hydrogen bonds for one stair Cytosine and
guanine pair with three in between and are equal
in size when compared DNA strands are just not
the same One is coding and one is called lame
(anticoding) They are opposite in direction and
this is called antiparallel in name Complimentary
nature of strands lets replication proceed just
as planned with A paring to T and G pairing to
C the fidelity is precise and quite grand
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DNA Methods

• 1) Extract
• 2) Quantitate
• 3) Distinguish
• Size
• Content
• Restriction Fragment Length Polymorphisms (RFLP)
• Polymerase Chain Reaction (PCR)

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• The base sequence can exhibit differences in
  length and content between individuals.
• Dr. Dre ... AAAGAAAGAAGAAAC...
• DMX ... AAAGAAAGAAGA...
• OutKast ... AAAGAAAGAAGT...
• SnoopDogg ... AAAGAAAGAAGA...
• Britney Spears ... AAAGAAAGAA...
• Christina Aguilera ... AAAGAAAGAT...
• Eminim ... AAAGAAAGC...
• NSYNC ... AAAGAAAGT...
• Boyz to Men ... AAAGAAAG
• Although different between individuals DNA is
  identical in every cell of an individuals body
  Some exceptionsidentical twinsdiseased
  individuals, mtDNA (sport analogs)

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RFLP Role Playing

• 1. Students are assigned a base.
• 2. Sequence is provided with a restriction site
  5GGCC3 at the end.
• 3. A person acts as the restriction enzyme and
  cuts the strand.
• 4. The gel (classroom) is loaded, power supply is
  turned on (lights) and fragments are asked to
  slink through the class toward the front () end.
• 5. Power is stopped and we visualize the
  difference in migration of the short and long
  fragment

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PCR based systems are rapid, require less
material than RFLP and less time for typing
Polymerase Chain Reaction PCR is simply
repeated rounds of DNA replication

• Molecular xeroxing
• Calvin and Hobbes example

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Replication of DNA is Semi ConservativeOne old
and one newhttp//dir.niehs.nih.gov/dirlmg/repl.h
tml
Enzymes of Replication DNA is replicated or
copied in our cells. When completed, the new
double strands consist of one old template and
one newly made strand- This is called semi
conservative replication. There are many enzymes
that are required. They include unwinding
(helicases, gyrases), priming (primases), copying
(DNA polymerases) and touch up enzymes (DNA
ligases).
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5-P

• DNA Replication
• 5 required ingredients (components)- primer,
  template, Mg, dntps, DNA polymerase-
  PTMDD-(please to make DNA doubled)
• DNA Polymerase catalyzes the template directed
  (A-T, G-C), incorporation of dNTPs (PP is
  released) forming a 3-5 phosphodiester linkage
• Direction of synthesis 5?3 using primer 3OH
  to attach incoming nucleotide

Primer
3-OH
3-OH
dNTP
Mg
Template Old
DNA polymerase
5-P
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Summary 1

• Why study DNA
• Law enforcement, evolution, agricultural, and
  human applications-medical diagnostics
• DNA Biology and Genetics
• DNA is contained in cells the basic unit of life
• Found in nuclei, mitochondria and chloroplasts
• Organized in chromosomes. Located at positions
  called loci and come in different forms or
  alleles.
• Homozygous if the same, heterozygous if different
• Alleles segregate independently and assort
  randomly when on different chromosomes. Random
  assortment is desired for forensic DNA loci.
• DNA Function and Structure
• DeoxyriboNucleic Acid blueprints of life
• Replication, Information storage and mutation
  RIM
• Central Dogma
• DNA-------RNA------protein
• transcription translation

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Summary 2

• DNA Structure and Function continued
• Bases of DNA are Adenine, Guanine, Cytosine and
  Thymine- Asian Guys Can Teach AGCT
• Base pairing is A to T and G to C- DNA is where
  its AT
• Sequence of Bases Store information- Like the
  sequence of numbers in a Phone Number
• Nucleotides are the building blocks (dNTPs)
  themselves made of phosphate base and sugar PBS-
  The only station Sierra and Gabriel can watch
• DNA base pairs- DNA velcro (David Letterman
• DNA Replication
• Semi-conservative- Half republican (old) /half
  democrat (new)
• Template directed with base pairing (AT, GC)
• 5 required ingredients- primer, template, Mg,
  dntps, DNA polymerase (PTMDD)