DNA Structure

1
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.

2
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
3
DNA Structure2 Complimentary, Antiparallel
Strands held together by Base Pairs- H Bonds
.
AT held with 2 H Bonds
GC held with 3 H Bonds
4
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). DNA replication is quite accurate in
our cells. The error rate is approximately 10-9
5
5-P

• PCR repeated rounds of 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