7.1 Introduction 7.2 Codon-anticodon recognition involves wobbling 7.3 tRNA contains modified bases that influence its pairing properties 7.4 (There are sporadic alterations of the universal code) 7.5 tRNAs are charged with amino acids by synthetases 7.6 Accuracy depends on proofreading 7.7 Suppressor tRNAs have mutated anticodons that read new codons 7.8 The accuracy of translation 7.9 tRNA may influence the reading frame

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

26.1 Introduction 26.2 Carriers and channels form water soluble paths through the membrane 26.3 Ion channels are selective 26.4 Neurotransmitters control channel activity 26.5 G proteins may activate or inhibit target proteins 26.6 G proteins function by dissociation of the trimer 26.7 Growth factor receptors are protein kinases 26.8 Receptors are activated by dimerization 26.9 Receptor kinases activate signal transduction pathways

17.1 Introduction 17.2 The mating pathway is triggered by pheromone-receptor interactions 17.3 The mating response activates a G protein 17.4 Yeast can switch silent and active loci for mating type 17.5 The MAT locus codes for regulator proteins 17.6 Silent cassettes at HML and HMR are repressed 17.7 Unidirectional transposition is initiated by the recipient MAT locus 17.8 Regulation of HO expression 17.9 Trypanosomes switch the VSG frequently during infection 17.10 New VSG sequences are generated by gene switching 17.11 VSG genes have an unusual structure 17.12 The bacterial Ti plasmid causes crown gall disease in plants 17.13 T-DNA carries genes required for infection 17.14 Transfer of T-DNA resembles bacterial conjugation 17.15 Selection of amplified genomic sequences 17.16 Transfection introduces exogenous DNA into cells 17.17 Genes can be injected into animal eggs 17.18 ES cells can be incorporated into embryonic mice 17.19 Gene targeting allows genes to be replaced or knocked out

9.1 Introduction 9.2 Transcription is catalyzed by RNA polymerase 9.3 The transcription reaction has three stages 9.4 A stalled RNA polymerase can restart 9.5 RNA polymerase consists of multiple subunits 9.6 RNA Polymerase consists of the core enzyme and sigma factor 9.7 Sigma factor is released at initiation 9.8 Sigma factor controls binding to DNA 9.9 Promoter recognition depends on consensus sequences

21.1 Introduction 21.2 Response elements identify genes under common regulation 21.3 There are many types of DNA-binding domains 21.4 A zinc finger motif is a DNA-binding domain 21.5 Steroid receptors are transcription factors 21.6 Steroid receptors have zinc fingers 21.7 Binding to the response element is activated by ligand-binding 21.8 Steroid receptors recognize response elements by a combinatorial code

13.1 Introduction 13.2 DNA polymerases are the enzymes that make DNA 13.3 DNA synthesis is semidiscontinuous 13.4 Coordinating synthesis of the lagging and leading strands 13.5 The replication apparatus of phage T4 13.6 Creating the replication forks at an origin 13.7 Common events in priming replication at the origin 13.8 Does methylation at the origin regulate initiation? 13.9 Licensing factor controls eukaryotic rereplication

第一节 果树的形态学特征 一 果树的一般特性 二 果树的树体结构 三 果树的枝芽特性 四 果树的叶与根系结构 第二节 果树的生长结果习性 一. 果树的生命周期及特点 二. 果树的年生长周期 三. 果树的花芽形成与开花 四. 果实的生长与发育 第三节 果树对环境条件的要求

The generation of metabolic energy is a major activity of all cells, and two cytoplasmic organelles are specifically devoted to energy metabolism and the production of ATP. Mitochondria are responsible for generating most of the useful energy from the breakdown of lipids and carbohydrates, and chloroplasts

一)被子植物起源的时间 被子植物的化石在白垩纪(1.36-0.9亿年)爆发性地大量出现,许多人弄不清原 因,如达尔文就说:“被子植物的起源简直是可恶的神秘事务