分子生物学(双语)1-Genes-Are-DNA.ppt

Chapter 1,Genes Are DNA,Figure CO:X chromosome in blue,Science VU/DOE/Visuals Unlimited,FIGURE SO:Part I:Genes and Chromosomes,Photo courtesy of S.V.Flores,A.Mena,and B.F.McAllister.Used with permission of Bryant McAllister,Department of Biology,University of Iowa.,FIGURE CO:Genes are DNA,Mopic/ShutterStock,Inc.,FIGURE 02:A gene codes for an RNA,which may code for protein,DNA as the Genetic Material,Pneumococcus,pathogenicity tranferred to normal strain by transformation,T2 bacteriophage genetic material is DNA,Transfection of eukaryotic cells with TK+,FIGURE 03:Griffith experiment,FIGURE 06:The genetic material of phage T2 is DNA,FIGURE 07:Eukaryotic cells can acquire a new phenotype as the result of transfection,FIGURE 08:A polynucleotide chain,FIGURE 14:Base pairing provides the mechanism for replicating DNA,FIGURE 13:The two strands of DNA form a double helix,Photodisc,FIGURE 15:Replication of DNA is semiconservative,FIGURE 16:The replication fork,FIGURE 17:An endonuclease cleaves a bond within a nucleic acid,FIGURE 18:An exonuclease removes bases one at a time,Gene Expression,Transcription,Reverse transcription,RNA processing,Translation,Post-translational modifications,Control of Gene Expression,Processes affected by control,Complexity from control,Regulatory elements,cis,-acting,trans,-acting,FIGURE 20:Nucleic acids all replicate by synthesis of complementary strands,FIGURE 21:The amount of nucleic acid in the genome varies over an enormous range,Hybridization,Nucleic acids hybridize by base pairing,Denaturation is ds to ss,Tm depends on sequence,Renaturation is ds to ss,Depends on complementarity,Intermolecular or intramolecular,Hybridization is the key to many methods,FIGURE 23:Denatured single strands of DNA can renature to give the duplex form,Mutations,Point mutations,Transitions versus transversions,Chemical mutagens or misincorporation,Reversions,Insertions and deletions,Frameshifts,One gene,one polypeptide,Loss-of-function or gain-of-function,Complementation of mutations means different genes,FIGURE 25:Mutation rates,FIGURE 26:Mutations can be induced by chemical modification of a base,FIGURE 27:Mutations can be induced,FIGURE 28:Point mutations and insertions can revert,but deletions cannot revert,FIGURE 29:Spontaneous mutations are concentrated at a hotspot,FIGURE 30:Deamination,FIGURE 31:Deamination,FIGURE 32:PSTV RNA,