Chapter 6 DNA Structure, Replication, and Recombination 6-1
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Sections to study6.1 ExperimentalevidenceforDNA as thegeneticmaterial6.2TheWatsonandCrickdoublehelixmodelofDNA6.3 Genetic information in DNA base sequence6.4DNAreplication6.5Recombination attheDNAlevel6-2
Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 6-2 Sections to study Sections to study 6.1 Experimental evidence for DNA as the genetic 6.1 Experimental evidence for DNA as the genetic material material 6.2 The Watson and Crick double helix model of DNA 6.2 The Watson and Crick double helix model of DNA 6.3 Genetic information in DNA base sequence 6.3 Genetic information in DNA base sequence 6.4 DNA replication 6.4 DNA replication 6.5 Recombination at the DNA level 6.5 Recombination at the DNA level
The genetic material must exhibit four majorcharacteristicsStorage ofinformationExpression ofinformationReplicationVariation by mutationmutationReplicationGenesAllelesnew genesExpressionRaw materialsfor evolutionTraits6-3
Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 6-3 Storage of information Storage of information Expression of information Expression of information Replication Replication Variation by mutation Variation by mutation The genetic material must exhibit four major The genetic material must exhibit four major characteristics characteristics Genes mutation Alleles new genes Raw materials for evolution Traits Expression Replication
What are genes composed of ?Protein?20 different subunits-greaterpotentialvariety of combinationsChromosomes contain moreChromosomeNucleuscomereprotein than DNA by weightDNA ? Only four different subunits maup DNA.arCellChromosomes contain lessDNAthan protein by weightOther molecules?6-4
Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 6-4 What are genes composed of ? What are genes composed of ? Protein ? Protein ? 20 different subunits 20 different subunits – greater greater potential variety of combinations potential variety of combinations Chromosomes contain more Chromosomes contain more protein than DNA by weight. protein than DNA by weight. DNA ? Only four different subunits make Only four different subunits make up DNA. up DNA. Chromosomes contain less DNA Chromosomes contain less DNA than protein by weight. than protein by weight. Other molecules ? Other molecules ?
6.1Experimental evidence forDNA asthegeneticmaterialUntil 1944, observations favored protein as the geneticmaterial.Proteins are abundant in the chromosomes.Proteins are well characterized chemicallyChromosomeNucleusslomereChemical stainingrevealed thatDNA isCentromerelocalizedalmostexclusively in thechromosomes.aicomaraCell6-5
Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 6-5 Proteins are abundant in the chromosomes. Proteins are abundant in the chromosomes. Proteins are well characterized chemically. Proteins are well characterized chemically. 6.1 Experimental evidence for DNA as 6.1 Experimental evidence for DNA as the genetic material the genetic material Chemical staining Chemical staining revealed that revealed that DNA is localized almost localized almost exclusively in the exclusively in the chromosomes. chromosomes. Until 1944, observations favored protein as the genetic material