清华大学：《分子生物学》（英文版）Chapter 1 Genes are DNA

Chapter 1 Genes are DNA 莘大

Chapter 1 Genes are DNA

DNA是遗传物质 DNA为双螺旋 DNA的复制是半保留的 本章主要内容 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 消当 遗传信息可由DNA或者RNA提供

DNA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

1865 Genes are particulate factors 1871 Discovery of nucleic acids 1.1 1903 Chromosomes are hereditary units Introduction 1910 Genes lie on chromosomes 1913 Chromosomes contain linear arrays of genes 1927 Mutat ions are phy sical changes in genes 1931 Recombinat ion is caused by crossing over 1944 DNA is the genetic mat erial 1945 A gene codes for protein 1951 First protein sequence 1953 DNA is a double helix 958 DNA replicates semiconseratively 1961 Genetic code is triplet Figure lI A briet 1977 Eukaryotic genes are interrupted history of genetics 1977 DNA can be sequenced 1995 First genome sequenced 消当

Figure 1.1 A brief history of genetics. 1.1 Introduction

Genes are dna 消当

Genes are DNA

1.2 DNA iS the genetic material Avirulent mutants of a virus have lost the capacity to Infect a host 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 消当

Avirulent mutants of a virus have lost the capacity to infect a host 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 the genetic material

Pneumacoccustyp Infe cton of mice use dies 1.2 DNA is the no oth bateria genetic material Heat- kiled smooth ba cteria mouse in es rough bade ria Mixture of Heat-kiled Cs smo oth ba dera rough bacteria Dead mouse has lie smo oth bacteria Figure 1.2 The transforming Extrad DNA M principle Is DNA Add to Iwe rough bateria ■■ 消当 Tran sformation

Figure 1.2 The transforming principle is DNA. 1.2 DNA is the genetic material

Bacteria are infected with phages labeled with sZP()in DNA or with 3os(o) in protein 1.2 DNA is the genetic material Separate phage coats and infe cted bacteria Phage coats contain 80%of Infected bacteria contain 70%o label I solate progeny phage particle Progeny phage s have 30 % of 32p label and <1% of 35s label Figure 1.3 The genetic material of phage 12 IS DNA 消当

Figure 1.3 The genetic material of phage T2 is DNA. 1.2 DNA is the genetic material

Cells that lack Tk gene cannot produce thymidine kinase and die in absence of thymidine 1.2 DNA is the 器 genetic material 器 Dead cells Add TKTDNA 参 Live cells Figure 1. 4 Eukaryotic cells 像器 can acquire a new phenotype 器象 as the result of transfection 像 by added DNA 象 Colony of Tk t cell 消当 Some cells ta ke up k gene descendants of transfected cell pile up into a colony

Figure 1.4 Eukaryotic cells can acquire a new phenotype as the result of transfection by added DNA. 1.2 DNA is the genetic material

1.3 NA is a double helix Antiparallel 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 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 crosses over its own axis 消当

Antiparallel 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 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 crosses over its own axis. 1.3 DNA is a double helix

1. 3 DNA is a double helix ucleotide subunit CH <py imidine base Fioure 5 CH2 A polynucleotide Purine base chain consists of a eries of 5C-3C ugar-phosphate links that form a backbone from which the bases Sugar-phosphate backbone protrude 消当

Figure 1.5 A polynucleotide chain consists of a series of 5￠-3￠ sugar-phosphate links that form a backbone from which the bases protrude 1.3 DNA is a double helix