Upload
solomon-golden
View
216
Download
0
Embed Size (px)
Citation preview
Lecture 26 - 27
DNA: THE GENETIC MATERIAL.
Table 12-1, p. 263
Fig. A, p. 86Acetabularia mediterranea (Mermaid’s wineglass)
Fig. 12-1, p. 261
Smooth, encapsulated, virulent
Rough, unencapsulated, avirulent
Fig. 12-2, p. 262
35
S Bacterial viruses grown in 35S to label
protein coat or 32P to label
DNA
32 P
Viruses infect bacteria
1
2
Fig. 12-2, p. 262
Agitate cells in blender
Agitate cells in blender
Separate by centrifugation
Separate by centrifugation
35
S
32 P
Bacteria in pellet contain 32P-labeled
DNA35S-labeled protein in
supernatant
3
4
5
Heinz Fraenkel-Conrat (1957)
Friedrich Miescher(1844-1895))
Phoebius Levene(1869-1940)
Erwin Chargaff (1905-2002)
Rosalind Franklin
The diagonal pattern of spots stretching from 11 to 5 and from 1 to 7 o’clock 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
Rosalind Franklin (1952)X-ray crystallography
Periodicity of 3.4 nm (= 10 nucleotides)Double helixUniform width of 2 nmBases are flat and perpendicular to the long axis of the molecule
Lecture 28 - 29
DNA REPLICATION.
Table 12-3, p. 270
DNA polymerase
Fig. 12-10, p. 271
Telomerase activity (1)
Telomerase activity (2)
Fig. 12-15, p. 276
Fig. 12-13b, p. 274
340 nm
The End.