Structures of the Purine and Pyrimidine Bases
Example of the Structure of a Nucleotide
Base
Nucleoside
Nucleotide
Chemical
Structure of a
Nucleic Acid
Voet Fig. 3-6
Double Helical
Structure of DNA
Note that the strands run
antiparallel
Note that the helix is 20 Å wide.
There are about 10 base pairs
per turn of the helix.
One turn of the helix is 34 Å
The base pairs are 3.4 Å apart
Voet Fig. 3-9
Major
groove
Base Pairing
Voet Fig. 23-1
Many proteins associate
With DNA through the
Major and Minor
grooves
Major
Groove
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Space-filling Model of B-DNA
Backbones of the strands are bright
green and bright red
The bases on the corresponding
backbones are lighter green and pink
Helical Structures
A-DNA
B-DNA
Z-DNA
Voet Fig. 23-2
Supercoiling of DNA
Supercoiled DNA
Relaxed DNA
Denaturation of DNA
Voet Fig. 23-15
Restriction Endonucleases
Voet Fig. 3-18
Restriction Digest
Cutting DNA with
Restriction
Endonucleases followed
by Analysis by Gel
Electrophoresis
A
C
B
A
C
B
Visualizing DNA
Fragments in Gels
Voet Fig. 3-20
Southern Analysis
Voet Fig. 23-28
Chain
Termination
Method of DNA
Sequencing
Voet Fig. 3-23
DNA Sequencing Instruments
Fluorescent dye-conjugated derivatives of the Dideoxynucleotides
can be used in DNA Sequencing Instruments
Automated Sequencing
Example of data obtained from a DNA sequencing reaction using
fluorescent (dye-conjugated) derivatives of dideoxynucleotides
Voet Fig. 3-25
Polymerase
Chain Reaction
Amplification of
DNA
Garrett and
Grisham Fig. 13-21
See Voet Fig. 3-32
Plasmids can Serve as Cloning
Vehicles (Vectors)
Voet Fig. 3-27
Construction of a Recombinant DNA
Voet Fig. 3-29
Selection of
Transformants
Vector DNAs must be capable
of replicating in the host cells
and must carry a selectable
marker
Selection of Transformants of Interest
Voet Fig. 3-31