Genes, DNA Replication, Mitotic Cell Division
Genes, DNA Replication, Mitotic Cell Division BIOL 121N
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This 15 page Class Notes was uploaded by Dominick Ramos on Friday September 25, 2015. The Class Notes belongs to BIOL 121N at Old Dominion University taught by DOUGLAS J MILLS in Fall 2015. Since its upload, it has received 39 views. For similar materials see GENERAL BIOLOGY I in Biological Sciences at Old Dominion University.
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Date Created: 09/25/15
BiollZlNGenes G ProteinCoupled Receptors Some adult stem cells use G protein coupled receptors to recognize specific go signals and other signals 0 G proteins are the target of many pharmaceuticals 0 Some cancers relate to abnormally activated G proteins G protein Enzyme CYTOPLASM inactive ADENYLATE CYCLASE o o PHOSPHOLIPASE c THE G PROTEIN SELFDEAOTIVATES AND THE GPCR IS DEACTIVATED AFTER ACTIVATING THE PROPER SIGNAL TRANSDUOTION PATHWAY ADVANCE FROM THE 31 0 PHASE To 5 PHASE 0 hmlimmmheycqmlmtshnewQi erJ hmleWygytuteecgmxsMELQEQULPQS C39VIrvm Tyrosine Kinase Receptors Some adult stem cells use tyrosine kinase receptors to recognize specific go signals and other signals 0 Scaffolding proteins localize and arrange all of the molecules necessary for signal transduction to occur MEL2ft i39l iK3939l 39lili39f Receptor tyrosine kinase proteins CYTOPLASM THE ADULT STEM CELL ADVANCES FROM THE G1 39 7 s39 eADp 9 Md PHASE TO THE 5 PHASE Activated tyrosine Fully activated receptor kinase regions tyrosine kinase Inactive amp relay proteins 0 0 Im e lwww omubecometchvLT wax 7M L quotI WV IUVWVCW n 1 htuml4 xrSnmniumIn uglym4 ggm 9glyg9glg3 l ocoptg 39 Bellinianaahnltivnlinnaamdssi mulling gln hit wwwdnatubememfvldeolsOMFHnKIlece torAnilmthn hilt Trwww MulbecoWwatchvaKPhleBU39 LigandGated Ion Channel Receptors Some cell types use ligand gated ion channel receptors to recognize specific ligands signals 0 Neurons nerve cells and muscle cells use ligand gated ion channel receptors to recognize neurotransmitters BiollZlNGenes 2 How Adult Stem Cells Recognize Hydrophilic GoSignals Hydrophilic molecules cannot directly diffuse across the cell membrane How Adult Stem Cells Recognize Hydrophobic GoSignals Hydrophobic molecules can directly diffuse across the cell membrane Defining a Gene A gene is a specific nucleotide sequence in a DNA molecule that codes for the 0 Amino acid sequence of a specific polypeptide 0 Nucleotide sequence of sa specific RNA molecule The RNA Genomes of retroviruses and other RNA viruses also contain genes How Genetic Instructions are Stored in a Gene The linear sequence of nucleotides in a gene corresponds to the linear sequence of amino acids in the polypeptide it encodes Both Strands in the Double Helix Contain Genes The Watson Strand contains genes The Crick Strand contains genes the Crick strand contains the complementary base pairs to pair with the Watson strand The Specific Parts of a Eukarvotic Gene Each gene contains the information to ensure that the cell will 0 Activate the gene only when the product is required 0 Read the instructions of the gene correctly THE PR39OMlDTlER SEQUENCE RECR UITS THE ENZYHES ANlD PROTEINS NECESSARY TO READ THE GENE 5 T Region TSequence 39ll39TIE TRANSCTRIIFTITON START SITE THE TRANTSCTRITPTlON STOP SITE SEQUENCE INSTR UCTS THE CELL SEQUENCE ITMSTRUCTS THE CELL WHERE To BEGIN READING THE WHERE TO STOP READTNG THE lINSTRUGTIONS IN THE GENE lINSTRU CTIlONS IN THE GlENlE BiollZlNGenes The Specific Parts of a Eukarvotic Gene Cont The nucleotide sequence of the exons determines the amino acid sequence of the polypeptide that the gene encodes The nucleotide sequence of the introns do not determine the amino acid sequence of the polypeptide that the gene encodes GENE EXON gxou exon 5 IIIIIIIIDJIIIIIHIIIIIIII IIIII IIIIIIIIquot 13 iNTRON INTRON W POLYPEPTIDE Why are introns in our genes if exons are used in determining amino acid sequence Some introns can code for specific proteins It all depends on what is needed with regards to polypeptide sequence BiollZlNGenes 4 THAT S ETUT GEE WEETEHE TTHAT AIT THETHHE TTF39EEHF HEEFTEEE THAT AnuLT ATEA EELLE EEH LIEETE ITEAAHIAIAHALATLIAAHAATAUAHAAT EEEEHIE TH EELE THET E EFFEETH UFL HEEEF TEH ELETE HI EI39HEL TEEH EEH ETIH E H EEEETH EEEEEIE HE E TTEEEHE Hi HEEE HEEE 39 H EE ETHEEHETHET E EAEIETHHL HEEETEHITIH T AH AHLT 5TH EELL HEHLT IH TH EHFITEEEIHH HF EEHEE THAT EEEU EHTET IHTH THE E FHAEET39 DEEHI HWHH HEquot LT ETEHELL WiiULE ITEHEHIIEH HTEHEHILEE HIEFEEL HTEEEHE39IEIE EEEfll iEiElHr EEHEEEHTHIWH THE IHETEU39ETIHETE HATE WHIEH TwilTTFE E ILHEIELEL HHLEU LEE WHIEH FHHTHF H HHAE39ETIE EEEH EWHTHIHE TH IHEEHHTIH THET EETIIETHEE THE EH EEIE EEEEIHEHEE F TITHE EILTEEE TEEETITHHE THE EEHE n EHEEEET TE HEEHHIT THEE EHETHIEE EED FHETEIHE HEEEEEEET TE HEEL THE EEHE E THETH ET THE EELIL WHERE EETH EEEII39TIE THE HEEE T TE LIJHETEEET THE EEEE HHEHE TE ETEE HEEETHE THE EEHE E EHE EEHEE LEEETEEH EETH ETHEH DEIEHETEEH E EEIEH ETHEHEEB F THE EHE EHELE HELTHT ITAH WE IHTEHTIHALLT HLTE TH HHELTIEE ELI E FEPE EIFI E EH5 TH EEEUE HEWFEITEIHEHH HEWEHE HEELEULEEWITH HEDI EAL HALHE T Biol121NDNA Replication 1 DNA Replication in the Nucleus o Occurs during the s phase of the cell cycle 0 Replicates the 31 billion nucleotide pairs in 68 hours 0 Must occur before the adult stem cell divides to ensure that each daughter cell has a complete set of genetic instructions genome DNA Replication Occurs in other organelles DNA replication will also occur in o The mitochondria of animal cells 0 Mitochondria and chloroplasts of plant amp algal cells DNA Replication Complex Replisome or DNA Replication Bodv All of the enzymes proteins and nucleotides required to make DNA are located together in the nucleus to form a quotDNA Replication Factory 0 There are multiple replisomes in the nucleus to increase the rate of DNA replication The Logic of DNA Replication 0 Each DNA strand of the double helix is a template for the synthesis of a new complementary strand 0 DNA polymerase 0 reads the sequence of each separated DNA strand to guide the synthesis of each new DNA strand 0 It also follows the rules of complementary base pairing when synthesizing a new strand of DNA DNA Replication Requires Specific Nucleotide Sequences Replication begins at origins of replication 0 There are many origins of replication sequences in each of our DNA molecules to increase the rate of DNA replication 0 quotDNA Initiator proteins bind to the origin of replication sequences to begin organizing DNA replication The enzymes and proteins required for DNA replication o HelicaseBreaks the Hbonds between complementary base pairs to unwind the double helix 0 Topoisomeraserelieves coiling tension in the DNA double helix due to its unwinding by heHcase Biol121NDNA Replication o Singlestrand binding proteins keep the two strands separated and reduce strand degradation Singlestrand binding Primase proteins Helicase The Function of Primase Primase makes a short complementary RNA strand quot11 nucleotides called a primer on each separated DNA strand 0 DNA polymerase enzymes that make new DNA strands require the 3 OH 3 prime hydroxyl end of the RNA primer to begin adding DNA nucleotides to make a new complementary DNA strand The Function of DNA polymerz DNA polymerase is the enzyme that adds nucleotides to the 3 OH end of the RNA primer to make the new complementary DNA strand Primase DlN39A template 3 5 539llllll 3 RNA primer DNA polymerase III N ew DN A lFE THE SCIENCE OF BIOLO o It follows the rules of complementary base pairing 0 11 human DNA polymerases have been identified 0 Human DNA polymerase adds 50 nucleotides per second 0 Bacteria DNA polymerase adds quot500 nucleotides per second 0 Another DNA polymerase removes the RNA primer and replaces it with a new DNA strand BiollZlNDNA Replication The Function of DNA Ligase DNA ligase links the 3 OH end to the 5 PO4 end to complete the synthesis of the new DNA strand 0 In a sense it seals the nicks in DNA molecules 3w 5 5w 3 DNA POLYMERASE 39 3 5 THE RNA PRIMER 5 3 l5 REMOVED DNA POLYMERASE 39 3quot 5 THE RNA PRIMER IS 5quot 3 REPLACED WITH DNA THESE TWO DNA MOLECULES MUST BE lIOINED TOGETHER DNA Replication Requires a Source of Energy The breaking of the energetic phosphate bonds in the four nucleoside triphosphates provides the energy for DNA polymerase to synthesize DNA New strand Template strand 5 end 3 end 5 end 3 end EN ERGY RICH BONDS i 0H Pyrophosphate 339 end Nucleoside 39 2 i triphosphate 5 end 5 end DNA Replication is an Extremely Precise Process Biol121NDNA Replication The error rate during DNA replication is low due to DNA polymerase s proofreading ability This is essential to maintain the integrity of the genetic instructions stored in our genes DNA polymerase detects and removes the mismatched nucleotide that has added DNA polymerase error rate is quot 10398 per base pair DNA repair enzymes further reduce the error rate to quot 1039 LO The result is 1 mutation for every 10 billion base pairs replicated The Ends of Our Linear DNA molecules require protection The exposed ends of our linear DNA molecules can be Degraded by enzymes called DNA nucleases Joined together to cause lethal mutations Telomeres Protect the Ends of Our DNA Molecules Telomeres are The protective caps on the ends of our linear DNA molecules Disposable ends of our linear DNA molecules Structures required to maintain DNA length and chromosome stability in adult stem cells Structures at the end of DNA molecules that consist of proteins and the DNA sequence TTAGGG repeated 1001000 times The enzyme Telomerase makes Telomeres Adult stem cells produce the enzyme telomerase to replenish the telomeres after each round of DNA replication Some telomere DNA is lost during replication because DNA polymerase cannot synthesize DNA at the ends of our linear DNA molecules Telomerase replaces the telomere DNA that was lost BiollZlNDNA Replication o This preserves the genes located near the end of the linear DNA molecules in the nucleus of our adult stem cells IIMIIIIHIIIII relomemsc bmds lo 3 flanking end of lelomere that us complementary to lelomerase RNA 1W Bases are added using RNA as template Telomerase relocates Second step is repeated DNA polymerase complements the laggrng strand I 4 BiollZlNDNA Replication 6 if n m WWW BREWERE5 DNA HEPLWMIFIW m AHMAL m mm 7 n a i iEFLliC l IH EEIFME EflLS HEDIMSE a lam HM l EPLlE l H EEMH S AT HWLEWIDE quotif MIA DLDEWLES 39E WHJIEHW 0F 39 E HM FDLWEHAEE U QE MMHEMWE EMA DURING WM REP39LiE TmH 39 mag Piamemgm Hu m rmm m THE EHO m THE Emma HOLEWLE mm PRIMER WW m inmmsae m we memm mm THE 0F F SCHEME W EEiLlLi WE W AIHTMH TELDHIEEESM THE EH3 03F MLEGULEB ELELLE PW U E E m I izE T E WELWEHJEE TIME EFliI m H 3 BiollZlNMitotic Cell Division In 61 DNA is condensed into in the nucleus of the cell Chromatin is consisted of 0 DNA 0 Histoneproteins CHROMATIN MOLECULES COMPRESS INTO CHROMOSOMES cnROMArm unms PROPHASE or MITOSIS p arm Centromere Chromosome USA National Library of Medicine Homologous Chromosomes Homologs TWO IDENUGIM E MQITERTIIAL SISTER THE Homomaoius mm on cHRurIIATIns cHRoMDSOMlE 1 7 w DUlRIlHG 5 PHASE W a Two IDENTIan FATERNAL SlISTER cIIFIomTIItIs GHROMOSOME 1 lFROMI mu SISTER CHROMATIDE IIIRE LINKED TOGETHER AT THE GENITIEDMERE SEQUEIHGE AlF39lI39ER nilIII RIEPLIlGATIDIN AFTER DNA REIPILIcATIOIII TIHERE ARE FDILIR GDFIES 0F BHRDIMGSOME 1 We inherit one complete set of chromosomes from our mother and father 0 The copies of chromosome 1 that we inherit from each of our parents mom and dad are an example of homologous chromosomes 0 Females have two copies of every gene one from mom and one from dad Mitotic Cell Division Is an Essential Process It provides all these functions in multi cell species 0 Growth 0 Repaw o Renewal BiollZlNMitotic Cell Division 0 Defense 0 Reproduction The Adult Stem Cell Divides by Mitotic Cell Division Mitotic cell division Occurs during the mitotic M phase of the cell cycle 0 Consists of mitosis and cytokinesis 0 Results in the production of two identical daughter cells with 46 chromosomes and a complete set of organelles Mitotic Cell Division Consists of Mitosis and Cytokinesis Mit05i5 NUCLEUS Two complete sets of chromosomes 46 are delivered to the opposite ends of the adult stem cell 0 When complete the adult stem cell briefly contains two MITOSIS nuclei 0 Each nucleus contains 46 chromatin molecules chromosomes 0 Mitosis ensures each daughter cell will receive a complete quotLEEE set of genetic instructions genome when the cell separates by cytokinesis Cytokinesis After mitosis is complete the adult stem cell separates into two identical daughter cells o Cytokinesis is the process of cell separation Jib J c Mitosis Contractile nng of Daughter cells microfilaments Proghase WW f ffrff t s ll o Chromatin is condensed into chromosomes with the assistance of condensing protein complexes 0 Spindle Formation begins Prometaphase Metaphase I o A kinetochore forms on each sister chromatid o The nuclear envelope dismantles to form membrane vesicles BiollZlNMitotic Cell Division 3 o The spindle microtubules attach to kinetochores Metaphase Metaphase II o the spindle properly positions each pair of sister chromatids at the center of the cell to start the delivery of each sister chromatid to the opposite ends of the cell Anaphase o The enzyme separase degrades the cohesion proteins that hold the sister ch romatids together 0 The spindle delivers each sister chromatid to opposite ends of the cell Telophase and Cytokinesis 0 After the sister chromatids completely separate the condensin protein complexes detach and the sister chromatids unwind to reform chromatin o The nuclear envelope reforms around the chromatin molecules through membrane vesicle fusion or endoplasmic reticulum envelopment The Function and Structure of the Spindle The spindle delivers two complete sets of chromosomes 46 to opposite ends of the adult stem cell during mitosis o The spindle is a dynamic structure consisting of many long protein filaments called microtubules 0 Each microtubule is formed by the polymerization of the protein tubulin Microtubules Chromosomes I Ill Overlapping 2quot nonkinetochore Kinetochore microtubules microtubules The Spindle Microtubules Attach to the Kinetochore On Each Sister Chromatid The kinetochore on each sister chromatid is formed from the interaction between specific proteins and the centromere DNA sequence BiollZlNMitotic Cell Division 0 A motor protein in the kinetochore enables each sister chromatid to move along the spindle microtubule towards one ends of the cell 15113 El 1161 iii Chromosome movement Kinetochore o 3 e Tubulin subun s Motor protein Chromosome Microtubule Mitotic Phase Checkpoint Failure M phase checkpoint failure can result in the nondisjunction of sister chromatids to cause aneuploidy o Aneuploidy the abnormal number of chromosomes in the nucleus Normal mitosis A FUNCTIONAL MilOSiS CHECKPOINT Twodaughtercells V THE CORRECT I MUHBER or gt l l c ROMOSOMES IIquot I I 139 TE lNUCLEUS or I l E CH DAUGHTER GELL Nondisjunction at anaphase Mitosis Two aneuploid daughter cells H ABNORMAL MUMEER or gt gt c lROMOSDMES in T E HucLEus OF A E cH DAUGHTER CELL A NONFUNCTIONAL CHECKPOINT BiollZlNMitotic Cell Division 5 TEEHT E ETUT ELITE ELI39EETIEHE wHTF IE MITHTIEiELL EIEIEIEIH EEHTILHL FHHEIHELEEELLEFEIE FE MULTIE ELL EFEIET THHHT TE HH EiHHTEHT H39H EEE E T L39IT39IZETEE 39iHiTHH EHHEELLET DE MIT TIWE EELL EWIEF39H TilquotF I I iHLIE39Iir FH HDME THE IEEHTIEHL MMEHTEH ELLE THE HEHIEHTIE1EL IMMEHTEH HELLE T THHT HUET EHH HEFLIEHTT39EH EEEHE EEFEHE EH HEULT ETEH ELL EHHEET THHHT TE THE FUHEEEE F HHEIET El HIHEEET lilliHI EH FEET HEHTTETHEEUHE ELI HIWHE EHEH ElF TH FIT ETHEEE F MITHEIE E 39ili EHEHi I THE EHEMHHH W LEELILEEi HEEHEE IH EHH iii E T H HT HIHET THE HHEEEHH HEHHHHE HTHHEEEHIETE HiEiiHE EEEHEHEHHEET H39HEH i3 THE EIJET EH EHHEHHTIJDE EEFHEIETE 39ili39HElili BEE THE HVLIELEE H EMMHE HEEHM HHIJlili i TIIIIE EHEHI iii E T lIiHHI EH ETHIJHTMHE EELIHHE TH EHHHATIEIE TEl A EH HHF THE AMLT 5TH ELL Eill HI I39llEa AHAF HAEE T 1H i THE EFIHEILE IETLIELILEE ll39ii39l39E ihiET W TI H EIETE El39iHliliTl T H39HHEHi FHETETHH THJTEEIEET WITH HHE HH THEH Til TEETH HIEEHTHIEHLEET THE Elli ii HEE FHiHiEi HT iiiglnlllil39ii EEEEEFIE VIII39iIiIE EE LiEHEE F E l39ii SETHTEE E HHHHT EE T HEW Ell HFEIT39HH FHETEEHE HLILEH HIHTEH EHHIEIHHTIE TE HWE HIEFJEITHIEHLEET EEEH EFIHELEEHEEHIHT FEILUEE HEEJLiLT iii EHEiJiF L iDT iii MEEHTEF EETLET THEME TEEEEEH E EHHEEHE HHHT EETE39IT39F EEHEEM39EEEHEEHULE E H THE HUELELJE F EH HEU LT ETEEH EELL THHT EEHF LETEE HITEEIE EHT DEE HT EEHF LETE ETTEHIHEEIET