分子生物学第一章基因是DNAGenesareDNA.ppt
《分子生物学第一章基因是DNAGenesareDNA.ppt》由会员分享,可在线阅读,更多相关《分子生物学第一章基因是DNAGenesareDNA.ppt(64页珍藏版)》请在启牛文库网上搜索。
1、Chapter 1Genes are DNADNA是遗传物质DNA为双螺旋DNA的复制是半保留的通过碱基配对进行核酸杂交突变改变了DNA的序列突变集中于热点顺反子是单个DNA片断多重等位基因的种类DNA的物理交换导致重组遗传密码是三联体细菌的基因和蛋白是共线性的顺式作用点和反式作用分子遗传信息可由DNA或者RNA提供 本章主要内容Figure 1.1 A brief history of genetics.1.1 IntroductionGenes are DNAAvirulent mutants of a virus have lost the capacity to infect a ho
2、st cell productively, that is, to make more virus.Transfection of eukaryotic cells is the acquisition of new genetic markers by incorporation of added DNA.Transforming principle is DNA that is taken up by a bacterium and whose expression then changes the properties of the recipient cell.1.2 DNA is t
3、he genetic materialFigure 1.2 The transforming principle is DNA. 1.2 DNA is the genetic materialFigure 1.3 The genetic material of phage T2 is DNA. 1.2 DNA is the genetic materialFigure 1.4 Eukaryotic cells can acquire a new phenotype as the result of transfection by added DNA. 1.2 DNA is the geneti
4、c materialAntiparallel strands of the double helix are organized in opposite orientation, so that the 5 end of one strand is aligned with the 3 end of the other strand.Base pairing describes the specific (complementary) interactions of adenine with thymine or of cytosine with thymine in a DNA double
5、 helix (the former is replaced by adenine with uracil in double helical RNA).Complementary base pairs are defined by the pairing reactions in double helical nucleic acids (A with T in DNA or with U in RNA, and C with G).Supercoiling describes the coiling of a closed duplex DNA in space so that it cr
6、osses over its own axis.1.3 DNA is a double helixFigure 1.5 A polynucleotide chain consists of a series of 5-3 sugar-phosphate links that form a backbone from which the bases protrude1.3 DNA is a double helixFigure 1.6 The double helix maintains a constant width because purines always face pyrimidin
7、es in the complementary A-T and G-C base pairs. The sequence in the figure is T-A, C-G, A-T, G-C.1.3 DNA is a double helixFigure 1.7 Flat base pairs lie perpendicular to the sugar-phosphate backbone. 1.3 DNA is a double helixFigure 1.8 The two strands of DNA form a double helix. 1.3 DNA is a double
8、helixDNA polymerases are enzymes that synthesize a daughter strand(s) of DNA (under direction from a DNA template). May be involved in repair or replication.DNAases are enzymes that attack bonds in DNA.Endonucleases cleave bonds within a nucleic acid chain; they may be specific for RNA or for single
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 分子生物学 第一章 基因 DNAGenesareDNA