molecular biology (.ppsx)
TRANSCRIPT
Molecular Biology
Molecular BiologyTodays TopicsChromosomesThe Double Helix - DNAThe Molecules of DNADNA ReplicationThe Central DogmaDNA TranscriptionDNA TranslationProteomics
Chapter 9
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Paired DNA Strands
Paired DNA Strands
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ChromosomesA eukaryotic chromosome is a molecule of DNA together with associated proteins.
ChromosomeStructure made of DNAand associated proteinsCarries a part of a cellsgenetic information
Source: www.beltina.org. 2015.
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DNA Packaging
DNA Packaging
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DNA StructureProteins organize DNA structurally.Histones allow chromosomesto pack tightly. Histone octomersType of protein that structurally organizes eukaryotic chromosomesNucleosomeA length of DNAwound around a spool of histone proteins
Naked DNA
Source: www.ncbe.reading.ac.uk. 2015.
Beads-on-a-stringNucleosomes
30 nm solenoid
Extended form of chromosome
Condensed sectionof chromatin
Chromosome(metaphase)
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Chromosome NumberA eukaryotic cells DNA is divided into a characteristic number of chromosomes.Chromosome numberSum of all chromosomesA human body cell has 23 pairsDiploidCells having two of each type of chromosome characteristic (2n)
Source: www.washington.edu. 2015.
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Examples of Chromosome NumberSpecies# Chrom.Fruit fly8Amoeba13Garden Pea14Frog26Cat38Human46Species# Chrom.Potato48Pineapple50Cow60Dog78Vizcacha rat102Horsetail216Adders Tongue1,260
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Examples of Chromosome Number
Source: www.flickr.com. 2015.
Source: www.highlanddiary.co.uk. 2015.Adders tonguefern (1,260)Vizcacha rat (102)
Source: www.planet-mammiferes.org. 2015.
Horsetail (216)A living fossilSource: en.wikipedia.org. 2015.
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Types of ChromosomesTwo types of eukaryotic chromosomes:autosomes and sex chromosomesAutosomesPaired chromosomes with same length,shape, centromere location, and genes Any chromosome other than a sexchromosome Sex chromosomesMembers of a pair of chromosomesthat differ between males and femalesLooking at the chromosomes,Which one is the Y chromosome?Which one is the X chromosome?
Source: www.washington.edu. 2015.
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KaryotypeThe karyotype of an organism reveals characteristics of an organisms chromosomes.
KaryotypeImage of an individualscomplement of chromosomes arrangedbysize,length,shape, andcentromere location12345678910111213141516171819202122
Source: fineartamerica.com. 2015.
Source: www.washington.edu. 2015.
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3/29/2017Paradise Valley Community CollegeChapter 6 - DNA Structure and Function
KaryotypingSource: S. Belliappa. Modified from slideshare.com. 2017.
Source: keyword-suggestions.com. 2017.KaryogramDigitize orphotograph
AnalyzemetaphasespreadDigest withtrypsinand stain
Spread cellson slideAddcolchicine(stops mitosisat metaphase)
MitosisinducedAdd toculture medium(3 days @ 37C)
5 mLvenousblood
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The Double Helix - DNA
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A DNA molecule consists of two strands of nucleotide monomers running in opposite directions and coiled into a double helix(a twisting staircase).Three parts of a DNA nucleotideOne nitrogen-containing base(Adenine, Thymine, Guanine, or Cytosine) A five-carbon sugar (pentose, deoxyribose)Three phosphate groupsThe Double Helix
Credit: Modified from Chris Bickel, spectrum.ieee.org. 2017.CytosineSource: Modified from commons.wikimedia.org. 2017.
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Fame and Glory
1916-2004
1905-2002Erwin ChargaffDiscovered the relationships between DNA bases, A, T, G, C.Rosalind Franklin & Maurice WilkinsDiscovered the basic structure of DNA by x-ray crystallographyJames Watson andFrancis CrickBuilt the first accurate model of a DNA molecule
1920-1958
1916-2004
1928-
1962
1962
1962
1949Photo 51
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The Double HelixTwo double-helix strands are held together by hydrogen bonds between nucleotide bases.Base-Pairing Rules (Chargaff) A pairs with T C pairs with G [A] ~ [T] [C] ~ [G]
Source: Modified from undsci.berkeley.edu. 2015.Guanine (G) Cytosine (C)Adenine (A) Thymine (T)
CGTA
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Its about the code, not the chemistry!TGCA
The single-letter codes can now be read into a computer to create the genome database.
AGTCCATTACGAAAATCGACTATCGAAGGGTAAAGGCTTATAAGCCATAGTCAGGTAATGCTTTTAGCTGATAGCTTCCCATTTCCGAATATTCGGTATC
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Patterns of Base Pairing The DNA sequence varies among species and among individualsEach species has characteristic DNA sequencesDNA sequenceThe order of nucleotide bases in a strand of DNABase pairs:TGTTCTATGTTTACTTAGTACCTCTTTAACAAGATACAAATGAATCATGGAGAAAT
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DNA Replication
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DNA ReplicationThe two strands of a DNA molecule are complementary.Their nucleotides match up according to base-pairing rules(G to C, T to A).Each strand is labelled to indicate directionality.five-prime to three-prime5533ACTATCGACTGTGATAGCTGAC
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DNA Replication
DNA ReplicationSource: interactmedical.co.uk. 2017.
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Semi-ConservativeReplication
TGATAACTATThe base sequences of both DNA molecules is identical.Each parent strand becomes a template for a new DNA strand.Free nucleotides match their opposite on each strand.As replication startsDNA unwinds.parentparentnewnewCGTTTTAAAA
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DNA Repair Mechanisms
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MutationsUncorrected errors in DNA replication may become mutations.Mutation: A permanent change in DNA sequence
Source: Modified from biology-igcse.weebly.com. 2017.correctcopyparentparentmutantcopy
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DNA, RNA, & Protein Synthesis
Replication: DNA to DNA (Not part of protein synthesis)Occurs before mitosis & meiosis ONLYDuplication of DNA during S stage of InterphaseTranscription: DNA to RNADNA blueprint of gene is decodedResult: RNATranslation: RNA to ProteinRNA decoded & reconstructed (mRNA)Result: ProteinTheCentralDogma
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DNA Replication
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DNA Replication in Action
ChromosomeOriginal DNAReplication ForkFreeNucleotidesFree NucleotidesDNA PolymeraseDNA PolymeraseLeading StrandLagging StrandSource: Modified from philschatz.com. 2016.
Helicase
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Molecular BiologyTodays TopicsChromosomesThe Double Helix - DNAThe Molecules of DNADNA ReplicationThe Central DogmaDNA TranscriptionDNA TranslationProteomics
Chapter 9
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The Central Dogma
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DNA, RNA, & Protein Synthesis
Replication: DNA to DNA (Not part of protein synthesis)Occurs before mitosis & meiosis ONLYDuplication of DNA during S stage of InterphaseTranscription: DNA to RNADNA blueprint of gene is decodedResult: RNATranslation: RNA to ProteinRNA decoded & reconstructed (mRNA)Result: ProteinTheCentralDogma
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TranscriptionCentral Dogma of Molecular Biology
TranslationDNARNAProteinGenetic Determinism
MakesMakes
Gene Product
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Transcription: DNA to mRNA
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DNA, RNA, & Protein Synthesis
Replication: DNA to DNA (Not part of protein synthesis)Occurs before mitosis & meiosis ONLYDuplication of DNA during S stage of InterphaseTranscription: DNA to RNADNA blueprint of gene is decodedResult: RNATranslation: RNA to ProteinRNA decoded & reconstructed (mRNA)Result: ProteinTheCentralDogma
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Translation: mRNA to Protein
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Codons-AnticodonsThe finished polypeptide
LHIMUAA
STOPUAC
LEUCINEGUA
HISTIDINE
ISOLEUCINEUAA
METHIONINEUAC
tRNA aaCODON
ANTICODONssDNAmRNA3 TACTAAGTACTATAAAATGA 55 AUGAUUCAUGAUAUUUUACU 3
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The Genetic CodeThere are 4 different letters within RNA.There are 20 different amino acids in a protein.How can 4 letters code for20 amino acids?Possible combinations of 4 letters:44 = 256 combinations
AUGUACGUACUACAUAAUGAGGUUCUAUGUUUACUUAGUACCUCUUUAUGA35
GUUGUCGUAGUGAla A
UCAGUCAGUUUUUCUUAUUGPhe FLeu L
CUUCUCCUACUGLeu L
AUUAUCAUAAUGIle IMet M
GUUGUCGUAGUGVal V
UCUUCCUCAUCGSer S
CCUCCCCCACCGPro P
ACUACCACAACGThr T
UAUUACUAAUAGTyr YStop Stop
CAUCACCAACAGHis H Gln Q
AAUAACAAAAAGAsn NLys K
UGUUGCUGAUGGCys CStopTyr W
CGUCGCCGACGGArg R
AGUAGCAGAAGGSer SArg R
GGUGGCGGAGGGGly G
GAUGACGAAGAGAsp DGlu E
UCGAUCGAUCGAUCGASecond LetterFirst LetterThird Letter L N N E V L C L L S T L L VYM
Stop
*
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Sidebar: Why All the Colors?
ATCUGCGATTACTAGCGACTCCGACTTATCUGCGATTACTAGCGACTCCGACTT
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eukaryotes & ProkaryotesEukaryotesNucleus (DNA within)RNA transcription occurs prior to protein translation in the nucleusMany RNA post-processing eventsGene expression is regulated at many levelsProkaryotesLack nucleusRNA transcription and protein translation are simultaneousNo RNA post-processing eventsGene expression is regulated at the transcriptional levelGene Expression (Protein Synthesis)
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Gene Expression (Protein synthesis)Prokaryotes
PlasmamembraneDNA
mRNA
ProteinsRibosomes
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Gene Expression (Protein synthesis)
NucleusDNACytosol
ProteinsMaturemRNA
Pre-mRNARibosomes
Eukaryotes
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Introns removedEnd-capping
Nuclear membraneEukaryotic Gene RegulationGene regulation is the process of turning genes on and off. Transcription rates altered byTranscription factorsEnhancer proteinsSilencers (DNA sequences)Insulators (DNA sequences)Promoters (TATA boxes)End-capping andremoval of introns is crucial.Golgi apparatus responsible for finishing protein and tagging it for delivery.
TranscriptioncontrolPreRNAsynthesiscontrolRNAtransportcontrolTranslationcontrolmRNAPrimarytranscript
ProteinDNAgeneTranslationTranscription
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Proteomics
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proteomics1986: Genomics: the study of the entire genome1994: Proteomics (protein + genomics)the entire set of proteins, produced or modified by an organism or systemthe next step in the study of biological systemsstudy the protein, then work back to the gene
Source: Modified from majordifferences.com. 2017.
GenomicsResearch
ProteomicsResearch
Source: Modified from tuniselyoum.maktoobblog.com. 2017.
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Cystic FibrosisGene is located on Chromosome 7The primary structure1,485 amino acidsThe secondary structure5 domainsThe tertiary structureGate for chloride ion transport
MQKTEKASIFSQSREEEVQDTRL
From the primary structure, deduce the mRNA and DNA of the gene.
CFTR: Cystic Fibrosis Transmembrane conductance Regulator
7q31.1
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Cystic Fibrosis
Mucus accumulates & bacteria grow, creatingrespiratory infectionsResult:Protein misfolded creating a conductancedefectLocus 508:Phenylalanine is deleted
Chloride ionsExtracellular MatrixCytoplasm
NormalAbnormal
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MQKTPLEKASIFSQIFFSWTKPILWKGYRQRLELSDIYQIHPGDSADNLSERLEREWDREVATSKKNPKLINALKRCFFWKFLFYGILLYLGEVTKAVQPLLLGRIIASYDRDNEHERSIAYYLAIGLCLLFVVRMLLLHPAIFGLHHIGMQMRIAMFSLIYKKTLKLSSKVLDKISTGQLVSLLSNNLNKFDEGLALAHFVWIAPLQVLLLMGLLWDLLQASAFCGLGFLIILALFQAWLGRMMMKYRDKRAGKINERLVITSQIIENIQSVKAYCWENAMEKIIETIRETELKLTRKAAYVRYFNSSAFFFSGFFVVFLSIVPHLLLDGISLRKIFTTISFSIVLRMAVTRQFPWAVQTWYDSLGVINKIQEFLQKEEYKSLEYNLTTTEVAMENVSASWDEGIGEFFEKAKLEVNGGNISNEDPSAFFSNFSLHVAPVLRNINFKIEKGQLLAIAGSTGAGKTSLLMMIMGELEPSAGKIKHSGRISFSPQVSWIMPGTIKENIVFGVSYDQYRYLSVIKACQLEEDISKFPEKDNTVLGEGGITLSGGQRARISLARAVYKDADLYLLDSPFSYLDLFTEKEIFESCVCKLMANKTRILVTSKVEQLKKADKVLILHEGSCYFYGTFSELQDQRPEFSSHLIGFDHFNAERRNSIITETLRRCSIDSDPTGVRNEVKNKSFKQVGDFSEKRKSSIINPRKSSRKFSVMQKSQPQMSGIEEEDVPAVQGERKLSLVPESDQGEASLPRSNIFNTGPTFQARRRQSVLNLMTRTSISQGSNAFATRKTSVRKMSVSSYSNSSFEVDIYNRRLSQDSILEVSEDINEEDLKECFLDDTDSPSTTTTWNTYLRFLTAHKNFIFILVFCIVIFLAEVVASSAGLWVLKSNAPVINTTSNGNGSEISDTLSVIVTHTSFYYVFYIYVGVVDSLLALGIFRGLPLVHSLISVSKVLHKKMLHAILHAPMSTFNTMRAGRILNRFSKDTAILDDILPLSIFDLTQLVLIVIGAITVVSLLEPYIFLATVPVIVAFILLRSYFLHTSQQLKQLESEARSPIFAHLITSLKGLWTLRAFGRQPYFETLFHKALNLHTANWFLYLSTLRWFQMTIEMIFVIFFIAVSFISIATSGAGEEKVGIVLTLAMNIMNTLQWAVNASIDVDSLMRSVSRIFRFIDLPVEELINENKNKEEQLSEVLIYENDYIKKTQVWPSGGQMTVKNLSANYIDGGNTVLENISFSLSPGQRVGLLGRTGSGKSTLLSAFLRLLSTQGDIQIDGVSWQTIPLQKWRKAFGVIPQKVFIFSGSIRKNLDPYGKWSDEELLKVTEEVGLKLIIDQFPGQLDFVLLDGGCVLSHGHKQLVCLARSVLSKAKILLLDEPSAHLDPITFQIIRKTLKHAFADCTVILSEHRLEAMLECQRFLVIEDNTVRQYDSIQKLVNEKSFFKQAISHSDRLKLFPLHRRNSSKRKSRPQISALQEETEEEVQDTRLProteomicsLDLFTELeu - Asp - Leu-Phe - Thr - Glu5055065075085095101,485 amino acids
LDLFTE1-letter code for each aa:3-letter code for each aa:This is only the primary structure.At this point we have no idea what the DNA will look like.Amino Acid Sequence for CFTR protein (primary structure)
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Deciphering the Protein
5 TTAGATCTTTTTACAGAA 3TTAGATCTTTTTACAGAA
5,952 possible RNA sequencesUUUUUAGAUUUAUUUACGGAAUUGGACUUGUUCACAGAGCUUCUUACCCUCCUCACUCUACUACUGCUGGAAACACUUGAUUUAUUAUUGCUUCUCCUACUGUUAUUGCUUCUCCUACUGDNA ContigAll possible codons
LDLFTELeu -Asp-Leu-Phe-Thr-Glu505506507508509510
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Molecular Biology
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