遗传学chapter06dna structure replication and recombination样式第二级第三级第四.pptx

Chapter 6 ;Outline of Chapter 6 ;How investigators pinpointed DNA as ;Discovery of DNA ;DNA – d eoxyribo n ucleic ;What Are Genes Composed of ? ;Bacterial Transformation Implicates ;Griffith ’ s Experiment ;Fig. 6.4 ;Conclusion from Griffith’s experiment: ;1931 – Oswald T. Avery found that bacterial ;Purification of the “Transforming Principle” ;1944 – Oswald T. Avery, Colin MacLeod, and Maclyn ;Hershey - Chase experiment ;DNA ’ s chemical constituents ;Waring blender experiment using T2 bacteriophage ;Fig. 6.6 ;What Is the Structure of DNA? ;DNA ’ s chemical constituents ;Fig. 6.9 ;Fig. 6.9 ;In 1952, King ’ s College, X - ray diffraction photograph ;According to Rosalind Franklin’s X-ray ;James Watson and Francis Crick ;Erwin Chargaff ’ s experiments demonstrate that ;Structurally, purines (A and G) pair best ;Complementary base pairing by formation of ;In 1953, James ;DNA is double helix. ;In 1962, James Watson, Francis Crick and Maurice ;DNA double helix may assume ;Some DNA molecules are circular instead of ;How does DNA replicate? ;Three ;The model of DNA replication postulated ;Fig. 6.16 ;Experimental Proof of ;Fig. 6.18 ;The Mechanism of DNA Replication ;Fig. 6.20 a ;Fig. 6.20 b ;Enzymes involved in DNA replication ;DNA replication is bidirectional ;The bidirectional replication of a ;Fig. 6.21 c-f ;Cells must ensure accuracy of their ;DNA bination: ;Meselson and Weigle Experiment ;Chiasmata: ;Heteroduplexes mark the spot of ;Heteroduplex region ;Gene Conversion ;Gene ;Double - strand break model of DNA