DNA: THE GENETIC MATERIAL.

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Lecture 26 - 27

• DNA THE GENETIC MATERIAL.

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Table 12-1, p. 263
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Acetabularia mediterranea (Mermaids wineglass)
Fig. A, p. 86
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Fig. 12-1, p. 261
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Smooth, encapsulated, virulent
Rough, unencapsulated, avirulent
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35S
32 P
Bacterial viruses grown in 35S to label protein
coat or 32P to label DNA
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Viruses infect bacteria
Fig. 12-2, p. 262
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Agitate cells in blender
Agitate cells in blender
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Separate by centrifugation
Separate by centrifugation
32 P
35S
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Bacteria in pellet contain 32P-labeled DNA
35S-labeled protein in supernatant
Fig. 12-2, p. 262
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Heinz Fraenkel-Conrat (1957)
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Friedrich Miescher (1844-1895))
Phoebius Levene (1869-1940)
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Erwin Chargaff (1905-2002)
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Rosalind Franklin
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The diagonal pattern of spots stretching from 11
to 5 and from 1 to 7 oclock provides evidence
for the helical structure of DNA. The elongated
horizontal patterns at the top and bottom
indicate that the purine and pyrimidine bases are
stacked 0.34 nm apart and are perpendicular to
the axis of the DNA molecule.
X-ray diffraction image of DNA
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• Rosalind Franklin (1952)
• X-ray crystallography
• Periodicity of 3.4 nm ( 10 nucleotides)
• Double helix
• Uniform width of 2 nm
• Bases are flat and perpendicular to the long
  axis of the molecule

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Lecture 28 - 29

• DNA REPLICATION.

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Table 12-3, p. 270
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DNA polymerase
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Fig. 12-10, p. 271
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Telomerase activity (1)
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Telomerase activity (2)
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Fig. 12-15, p. 276
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340 nm
Fig. 12-13b, p. 274
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The End.
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