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

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

Double Helical Structure of DNA

Voet Fig. 3-9

Major groove

Base Pairing

Voet Fig. 23-1

Many proteins associateWith DNA through theMajor and Minor grooves

MajorGroove

http://www.clunet.edu/BioDev/omm/gallery.htm

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

Cutting DNA with Restriction Endonucleases followed by Analysis by Gel Electrophoresis

Restriction Digest

A BC

AC

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

Fluorescent dye-conjugated derivatives of the Dideoxynucleotides can be used in DNA Sequencing Instruments

DNA Sequencing Instruments

Example of data obtained from a DNA sequencing reaction using fluorescent (dye-conjugated) derivatives of dideoxynucleotides

Automated Sequencing

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

Vector DNAs must be capable of replicating in the host cells and must carry a selectable marker

Selection of Transformants

Selection of Transformants of Interest

Voet Fig. 3-31