Abstract image of a woman sitting on books and studying on a laptop

Cell cycle... Cell Reproduction

Download as PPT, PDF
Microbiology, profile picture
Microbiology

The document discusses the cell cycle and types of cell reproduction, including asexual and sexual reproduction. It details the processes of mitosis and meiosis, highlighting their phases and significance in cell division for eukaryotic organisms. Additionally, it covers the implications of uncontrolled mitosis, such as cancer development.

Education
1 of 86
Downloaded 15 times
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
1
ASSIGNMENT # 03 • Prepared by Amjad Khan • Submitted to Dear, Sir Ghadir Ali • Program BS Microbiology 3th • Subject CELL BIOLOGY • Topic CELL CYCLE • Date 12th January, 2015 2
3 CellCell ReproductionReproduction
4 TypES of CEllTypES of CEll REpRoduCTIoNREpRoduCTIoNAsexual reproductionAsexual reproduction involves ainvolves a single cellsingle cell dividing to makedividing to make 2 new,2 new, identical daughter cellsidentical daughter cells Mitosis & binary fissionMitosis & binary fission areare examples of asexual reproductionexamples of asexual reproduction Sexual reproductionSexual reproduction involves twoinvolves two cells (egg & sperm) joining to make acells (egg & sperm) joining to make a new cell (zygote)new cell (zygote) that isthat is NOTNOT identical to the original cellsidentical to the original cells MeiosisMeiosis is an exampleis an example
Division Mechanisms Prokaryotic organisms – Binary fission Eukaryotic organisms – Mitosis • Karyokinesis (division of nucleus) • Cytokinesis (division of cytoplasm) – Meiosis
6 CEll dIvISIoN INCEll dIvISIoN IN pRokARyoTESpRokARyoTES
7 Cell Division in ProkaryotesCell Division in Prokaryotes  Prokaryotes such asProkaryotes such as bacteriabacteria divide into 2divide into 2 identical cells by theidentical cells by the process ofprocess of binarybinary fissionfission  Single chromosomeSingle chromosome makes a copy ofmakes a copy of itselfitself  Cell wall formsCell wall forms between thebetween the chromosomes dividingchromosomes dividing the cellthe cell ParentParent cellcell 2 identical daughter cells2 identical daughter cells ChromosomeChromosome doublesdoubles Cell splitsCell splits
8 Prokaryotic CellProkaryotic Cell Undergoing Binary FissionUndergoing Binary Fission
9 Animation of Binary FissionAnimation of Binary Fission
10 TheThe CellCell CycleCycle
11 Five Phases of the Cell CycleFive Phases of the Cell Cycle GG11 - primary growth/gap phase- primary growth/gap phase S – synthesis; DNA replicatedS – synthesis; DNA replicated GG22 - secondary growth/gap- secondary growth/gap phasephase collectively these 3 stages arecollectively these 3 stages are calledcalled interphaseinterphase M - mitosisM - mitosis C - cytokinesisC - cytokinesis
12 Cell CycleCell Cycle
13 Interphase - GInterphase - G11 StageStage 11stst growth/gap stagegrowth/gap stage after cellafter cell divisiondivision CellsCells maturemature by making moreby making more cytoplasm & organellescytoplasm & organelles Cell carries on itsCell carries on its normalnormal metabolic activitiesmetabolic activities i.e.i.e. respiration, digestion etc.respiration, digestion etc.
14 Interphase – S StageInterphase – S Stage SynthesisSynthesis stagestage DNADNA is copied oris copied or replicatedreplicated TwoTwo identicalidentical copiescopies of DNAof DNA OriginalOriginal DNADNA
15 Interphase – GInterphase – G22 StageStage 22ndnd Growth/GapGrowth/Gap StageStage OccursOccurs after DNA has been copie;after DNA has been copie; also in preparation for M phasealso in preparation for M phase All cellAll cell structures needed forstructures needed for divisiondivision are made (e.g. centrioles)are made (e.g. centrioles) BothBoth organelles & proteinsorganelles & proteins areare synthesizedsynthesized
16 What’s Happening in Interphase?What’s Happening in Interphase? What the cell looks likeWhat the cell looks like Animal Cell What’s occurring
17 Sketch the Cell CycleSketch the Cell Cycle DaughterDaughter CellsCells DNA CopiedDNA Copied CellsCells MatureMature Cells prepare forCells prepare for DivisionDivision Cell Divides intoCell Divides into Identical cellsIdentical cells
18 MitosisMitosis
19 MitosisMitosis Division of theDivision of the nucleusnucleus (karyokinesis)(karyokinesis) Division of theDivision of the cytoplasmcytoplasm (cytokinesis)(cytokinesis) Only occurs inOnly occurs in eukaryoteseukaryotes HasHas fourfour stagesstages Doesn’t occur inDoesn’t occur in some cells such assome cells such as brain cellsbrain cells
20 Four Mitotic StagesFour Mitotic Stages ProProphasephase MetaMetaphasephase AnaAnaphasephase TeloTelophasephase
21 Early ProphaseEarly Prophase ChromatinChromatin in nucleus condenses toin nucleus condenses to formform visible chromosomesvisible chromosomes Mitotic spindleMitotic spindle forms from fibers informs from fibers in cytoskeleton orcytoskeleton or centrioles (animal)centrioles (animal) ChromosomesChromosomes NucleolusNucleolus CytoplasmCytoplasm Nuclear MembraneNuclear Membrane
22 Late ProphaseLate Prophase Nuclear membrane & nucleolusNuclear membrane & nucleolus areare broken downbroken down ChromosomesChromosomes continue condensing &continue condensing & areare clearly visibleclearly visible Spindle fibers calledSpindle fibers called kinetochoreskinetochores attach to the centromereattach to the centromere of eachof each chromosomechromosome SpindleSpindle finishes forming between thefinishes forming between the poles of the cellpoles of the cell
23 Late ProphaseLate Prophase Nucleus & Nucleolus have disintegratedNucleus & Nucleolus have disintegrated ChromosomesChromosomes
24 Spindle Fiber attached toSpindle Fiber attached to ChromosomeChromosome Kinetochore FiberKinetochore Fiber ChromosomeChromosome
25 Review of ProphaseReview of Prophase What the cellWhat the cell looks likelooks like What’s happeningWhat’s happening
26 Spindle FibersSpindle Fibers The mitoticThe mitotic spindlespindle form from theform from the microtubulesmicrotubules in plantsin plants andand centriolescentrioles in animal cellsin animal cells Polar fibersPolar fibers extend from one pole ofextend from one pole of the cell to the opposite polethe cell to the opposite pole Kinetochore fibersKinetochore fibers extend from theextend from the pole to the centromere of thepole to the centromere of the chromosome to which they attachchromosome to which they attach AstersAsters are short fibers radiatingare short fibers radiating from centriolesfrom centrioles
27 Sketch The SpindleSketch The Spindle
28 MetaphaseMetaphase Chromosomes, attached to theChromosomes, attached to the kinetochore fiberskinetochore fibers, move to the center, move to the center of the cellof the cell Chromosomes are now lined up at theChromosomes are now lined up at the equatorequator Pole ofPole of the Cellthe Cell Equator of CellEquator of Cell
29 MetaphaseMetaphase AsterAster Chromosomes at EquatorChromosomes at Equator
30 Review of MetaphaseReview of Metaphase What the cell looksWhat the cell looks likelike What’sWhat’s occurringoccurring
31 AnaphaseAnaphase OccursOccurs rapidlyrapidly SisterSister chromatidschromatids areare pulled apart topulled apart to opposite polesopposite poles of the cell byof the cell by kinetochorekinetochore fibersfibers
32 Anaphase ReviewAnaphase Review What theWhat the cell lookscell looks likelike What’sWhat’s occurringoccurring
33 TelophaseTelophase Sister chromatids atSister chromatids at oppositeopposite polespoles SpindleSpindle disassemblesdisassembles Nuclear envelopeNuclear envelope forms aroundforms around each set of sister chromatidseach set of sister chromatids NucleolusNucleolus reappearsreappears CYTOKINESISCYTOKINESIS occursoccurs Chromosomes reappear asChromosomes reappear as chromatinchromatin
34 Comparison of Anaphase & TelophaseComparison of Anaphase & Telophase
35 CytokinesisCytokinesis Means division of the cytoplasmMeans division of the cytoplasm DivisionDivision of cell into two,of cell into two, identical halves calledidentical halves called daughterdaughter cellscells In plant cells, cell plateIn plant cells, cell plate formsforms at the equator to divide cellat the equator to divide cell In animal cells,In animal cells, cleavage furrowcleavage furrow forms to split cellforms to split cell
36 CytokinesisCytokinesis Cleavage furrowCleavage furrow in animal cellin animal cell Cell plate inCell plate in animal cellanimal cell
37 Mitotic StagesMitotic Stages
38 Daughter Cells of MitosisDaughter Cells of Mitosis Have theHave the same number ofsame number of chromosomes as each otherchromosomes as each other and asand as the parent cellthe parent cell from which theyfrom which they were formedwere formed IdenticalIdentical to each other, butto each other, but smallersmaller than parent cellthan parent cell MustMust grow in sizegrow in size to become matureto become mature cellscells (G(G11 of Interphase)of Interphase)
39 Identical Daughter CellsIdentical Daughter Cells Chromosome number theChromosome number the samesame, but cells, but cells smallersmaller than parent cellthan parent cell What isWhat is the 2nthe 2n oror diploiddiploid number?number? 22
40 ReviewReview ofof MitosisMitosis
41 Draw & Learn these StagesDraw & Learn these Stages
42 Draw & Learn these StagesDraw & Learn these Stages
43 InterphaseInterphase ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase Name the Mitotic Stages:Name the Mitotic Stages: Name this?Name this? Name this?Name this?
44 Eukaryotic Cell DivisionEukaryotic Cell Division  Used forUsed for growth andgrowth and repairrepair  Produce two new cellsProduce two new cells identical to the originalidentical to the original cellcell  Cells areCells are diploid (2n)diploid (2n) Chromosomes duringChromosomes during Metaphase of mitosisMetaphase of mitosis ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase CytokinesisCytokinesis
45 Mitosis AnimationMitosis Animation Name each stage as you see it occur?Name each stage as you see it occur?
46 Mitosis in Onion Root TipsMitosis in Onion Root Tips Do you see any stages of mitosis?Do you see any stages of mitosis?
47 Locate the Four MitoticLocate the Four Mitotic Stages in PlantsStages in Plants MetaphaseMetaphase ProphaseProphase AnaphaseAnaphase TelophaseTelophase
48 Uncontrolled Mitosis  If mitosis is notIf mitosis is not controlledcontrolled, unlimited, unlimited cell division occurscell division occurs causing cancerouscausing cancerous tumorstumors  OncogenesOncogenes are specialare special proteinsproteins that increase the chanceincrease the chance that a normal cellthat a normal cell develops into adevelops into a tumortumor cellcell Cancer cellsCancer cells
49 MeiosisMeiosis Formation of GametesFormation of Gametes (Eggs & Sperm)(Eggs & Sperm)
Words to knoW Gametes - reproductive cells that unite during sexual reproduction to form a new cell called a zygote (male = sperm, female = egg cell) Germ cells – sperm or egg cells Somatic cells - any cell other than the reproductive cells Diploid - a cell that contains two sets of chromosomes (2n), as normally found in somatic cells Haploid - have one set of chromosomes (n=1) as in germ cells, or half as many as a somatic cell Homologous – chromosomes that are alike in structure and genes Alleles – different forms of a gene ex. if talking about hair color as the gene, different alleles would be different colors like red, blonde, black etc. 50
51 Facts About MeiosisFacts About Meiosis Preceded by interphase whichPreceded by interphase which includesincludes chromosome replicationchromosome replication TwoTwo meiotic divisions:meiotic divisions: Meiosis IMeiosis I and Meiosis IIand Meiosis II AkaAka reduction-divisionreduction-division Original cell is diploid (2n)Original cell is diploid (2n) Four daughter cellsFour daughter cells produced thatproduced that areare haploid (n)haploid (n)
52 Facts About MeiosisFacts About Meiosis Daughter cellsDaughter cells contain half the numbercontain half the number of chromosomesof chromosomes as the original cellas the original cell ProducesProduces gametesgametes (eggs & sperm(eggs & sperm)) Occurs in theOccurs in the testestestes in malesin males ((SpermatogenesisSpermatogenesis)) Occurs in theOccurs in the ovariesovaries in femalesin females ((OogenesisOogenesis)) Human diploid cells haveHuman diploid cells have 46 chromosomes46 chromosomes (2n=46)(2n=46) Human sperm and egg cells haveHuman sperm and egg cells have 2323 chromosomes (n=23) eachchromosomes (n=23) each
53  Start withStart with 46 double stranded46 double stranded chromosomes (2n)chromosomes (2n) After 1 division -After 1 division - 23 double23 double stranded chromosomes (n)stranded chromosomes (n) After 2nd division -After 2nd division - 23 single23 single stranded chromosomes (n)stranded chromosomes (n)  Occurs in ourOccurs in our germ cellsgerm cells More Meiosis FactsMore Meiosis Facts
54 Why Do we Need Meiosis?Why Do we Need Meiosis? It is the fundamental basis ofIt is the fundamental basis of sexual reproductionsexual reproduction Two haploid (1n) gametes areTwo haploid (1n) gametes are brought together throughbrought together through fertilizationfertilization to form a diploidto form a diploid (2n) zygote(2n) zygote
55 Fertilization – “Putting itFertilization – “Putting it all together”all together” 1n =31n =3 2n = 62n = 6
56 Replication of ChromosomesReplication of Chromosomes ReplicationReplication is theis the process ofprocess of duplicating aduplicating a chromosomechromosome OccursOccurs prior toprior to divisiondivision Replicated copiesReplicated copies are calledare called sistersister chromatidschromatids Held together atHeld together at centromerecentromere Occurs inOccurs in InterphaseInterphase
57 A Replicated ChromosomeA Replicated Chromosome HomologuesHomologues (same genes,(same genes, different alleles)different alleles) SisterSister ChromatidsChromatids (same genes,(same genes, same alleles)same alleles) Gene XGene X Homologues separate in meiosis I andHomologues separate in meiosis I and therefore different alleles separate.therefore different alleles separate.
58 Meiosis Forms Haploid GametesMeiosis Forms Haploid Gametes  Meiosis mustMeiosis must reduce the chromosome numberreduce the chromosome number by halfby half  Fertilization then restoresFertilization then restores the 2n numberthe 2n number from mom from dad child meiosis reduces genetic content too much! The right number!
59 Meiosis: Two Part CellMeiosis: Two Part Cell DivisionDivision HomologuesHomologues separateseparate SisterSister chromatidschromatids separateseparate DiploidDiploid MeiosisMeiosis II MeiosisMeiosis IIII DiploidDiploid HaploidHaploid
60 Meiosis I: Reduction DivisionMeiosis I: Reduction Division NucleusNucleus SpindleSpindle fibersfibers NuclearNuclear envelopeenvelopeEarlyEarly Prophase IProphase I (Chromosome(Chromosome numbernumber doubleddoubled)) LateLate ProphaseProphase II MetaphaseMetaphase II AnaphaseAnaphase II Telophase ITelophase I (diploid)(diploid)
61 Prophase IProphase I Early prophaseEarly prophase HomologuesHomologues pair.pair. Crossing overCrossing over occursoccurs. Late prophaseLate prophase Chromosomes condense.Chromosomes condense. Spindle forms.Spindle forms. Nuclear envelopeNuclear envelope fragments.fragments.
62 Tetrads Form in Prophase ITetrads Form in Prophase I Homologous chromosomesHomologous chromosomes (each with sister chromatids)(each with sister chromatids) Join to form aJoin to form a TETRADTETRAD Called SynapsisCalled Synapsis
63 Crossing-OverCrossing-Over  HomologousHomologous chromosomeschromosomes in ain a tetradtetrad cross overcross over each othereach other  Pieces ofPieces of chromosomes orchromosomes or genes aregenes are exchangedexchanged  ProducesProduces GeneticGenetic recombinationrecombination inin the offspringthe offspring •Occurs in nonsister chromatids •Increases genetic variability Genetic recombination in which a strand of the genetic material (DNA/RNA)is broken and then joined to the end of a different DNA molecule.
64 Homologous ChromosomesHomologous Chromosomes During Crossing-OverDuring Crossing-Over
65 Crossing-over multiplies the already hugeCrossing-over multiplies the already huge number of different gamete typesnumber of different gamete types produced by independent assortmentproduced by independent assortment Crossing-OverCrossing-Over
66 Metaphase IMetaphase I Homologous pairsHomologous pairs of chromosomesof chromosomes align along thealign along the equatorequator of theof the cellcell
67 Anaphase IAnaphase I Homologues separateHomologues separate andand move to opposite poles.move to opposite poles. Sister chromatidsSister chromatids remainremain attachedattached at theirat their centromerescentromeres.
68 Telophase ITelophase I Nuclear envelopesNuclear envelopes reassemble.reassemble. Spindle disappears.Spindle disappears. CytokinesisCytokinesis divides celldivides cell into two.into two.
69 Meiosis IIMeiosis II Only one homologue of eachOnly one homologue of each chromosome is present inchromosome is present in the cellthe cell. Meiosis II produces gametes withMeiosis II produces gametes with one copy of each chromosome andone copy of each chromosome and thus one copy of each gene.thus one copy of each gene. Sister chromatids carrySister chromatids carry identical geneticidentical genetic informationinformation.. Gene XGene X
70 Meiosis II: ReducingMeiosis II: Reducing Chromosome NumberChromosome Number ProphaseProphase IIII MetaphaseMetaphase IIII AnaphaseAnaphase IIII TelophaseTelophase IIII 4 Identical4 Identical haploid cellshaploid cells
71 Prophase IIProphase II Nuclear envelopeNuclear envelope fragments.fragments. Spindle forms.Spindle forms.
72 Metaphase IIMetaphase II Chromosomes alignChromosomes align alongalong equatorequator of cellof cell..
73 Anaphase IIAnaphase II Sister chromatidsSister chromatids separate andseparate and move tomove to oppositeopposite polespoles. EquatorEquator PolePole
74 Telophase IITelophase II Nuclear envelopeNuclear envelope assembles.assembles. ChromosomesChromosomes decondense.decondense. Spindle disappears.Spindle disappears. Cytokinesis dividesCytokinesis divides cell into two.cell into two.
75 Results of MeiosisResults of Meiosis Gametes (egg & sperm)Gametes (egg & sperm) formform Four haploid cells withFour haploid cells with one copy of eachone copy of each chromosomechromosome One allele of each geneOne allele of each gene Different combinations ofDifferent combinations of alleles for differentalleles for different genes along thegenes along the chromosomechromosome
76 GametogenesisGametogenesis OogenesisOogenesis oror SpermatogenesisSpermatogenesis
77 SpermatogenesisSpermatogenesis Occurs in theOccurs in the testestestes Two divisionsTwo divisions produce 4produce 4 spermatidsspermatids SpermatidsSpermatids maturemature into sperminto sperm Men produce aboutMen produce about 250,000,000250,000,000 sperm per daysperm per day
78 Spermatogenesis in theSpermatogenesis in the TestesTestes SpermatidSpermatid
79 SpermatogenesisSpermatogenesis
80 OogenesisOogenesis Occurs in theOccurs in the ovariesovaries Two divisions produceTwo divisions produce 3 polar bodies3 polar bodies that die andthat die and 1 egg1 egg Polar bodies die because ofPolar bodies die because of unequalunequal division of cytoplasmdivision of cytoplasm Immature egg calledImmature egg called oocyteoocyte Starting at puberty, one oocyteStarting at puberty, one oocyte matures into anmatures into an ovum (egg)ovum (egg) every 28every 28 daysdays
81 Oogenesis in the OvariesOogenesis in the Ovaries
82 OogenesisOogenesis OogoniumOogonium (diploid)(diploid) MitosisMitosis PrimaryPrimary oocyteoocyte (diploid)(diploid) Meiosis IMeiosis I SecondarySecondary oocyteoocyte (haploid)(haploid) Meiosis IIMeiosis II (if fertilization(if fertilization occurs)occurs) First polar bodyFirst polar body may dividemay divide (haploid)(haploid) PolarPolar bodiesbodies diedie Ovum (egg)Ovum (egg) SecondSecond polar bodypolar body (haploid)(haploid) a A X X a X A X a X a X MatureMature eggegg A X A X
83 ComparingComparing Mitosis andMitosis and MeiosisMeiosis
84 MitosisMitosis MeiosisMeiosis Number ofNumber of divisionsdivisions 11 22 Number ofNumber of daughter cellsdaughter cells 22 44 GeneticallyGenetically identical?identical? YesYes NoNo Chromosome #Chromosome # Same as parentSame as parent Half of parentHalf of parent WhereWhere Somatic cellsSomatic cells Reproductive cellsReproductive cells WhenWhen Throughout lifeThroughout life At sexual maturityAt sexual maturity RoleRole Growth andGrowth and repairrepair Sexual reproductionSexual reproduction Comparison of DivisionsComparison of Divisions
85 Meiosis Mitosis Definition: A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes in a diploid cell. A process of asexual reproduction in which the cell divides in two producing a replica, with an equal number of chromosomes in haploid cell Function: sexual reproduction Cellular Reproduction & general growth and repair of the body Type of Reproduction: Sexual Asexual Occurs in: Humans, animals, plants, fungi all organisms Genetically: different identical Crossing Over: Yes, mixing of chromosomes can occur. No, crossing over cannot occur. Pairing of Homologues: Yes No Number of Divisions: 2 1 Number of Haploid Daughter Cells produced: 4 2 Chromosome Number: Reduced by half Remains the same Steps: The steps of meiosis are Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II and Telophase II. The steps of mitosis are Interphase, Prophase, Metaphase, Anaphase, Telophase and Cytokinesis Karyokenesis: Occurs in Interphase I Occurs in Interphase Cytokenesis: Occurs in Telophase I & Telohpase II Occurs in Telophase Centromeres Split: The centromeres do not separate during anaphase I, but during anaphase II The centromeres split during Anaphase Creates: Sex cells only: Female egg cells or Makes everything other than sex
End….. 86

More Related Content

PPTX
Cell adhesion molecules
Mital Chandegara
 
PPT
Chapter 8 by Karp (part2)
Geonyzl Alviola
 
PDF
Cell cycle inhibitor
thomasm2014
 
PPTX
Immunogenetics 30 12-14
Yahya Noori, Ph.D
 
PPTX
INFLAMMATORY RESPONSE IN HUMANS AND IT FUNCTION
ssri37388
 
PPTX
Baculovirus Expression Vector Systems
Brianna Bibel
 
PPTX
Cancer stem cells
BibiAyesha11
 
PPT
7-2: Eukaryotic Cell Structure
petruccis
 
Cell adhesion molecules
Mital Chandegara
 
Chapter 8 by Karp (part2)
Geonyzl Alviola
 
Cell cycle inhibitor
thomasm2014
 
Immunogenetics 30 12-14
Yahya Noori, Ph.D
 
INFLAMMATORY RESPONSE IN HUMANS AND IT FUNCTION
ssri37388
 
Baculovirus Expression Vector Systems
Brianna Bibel
 
Cancer stem cells
BibiAyesha11
 
7-2: Eukaryotic Cell Structure
petruccis
 

What's hot (13)

PPTX
Metodos anticonceptivos hormonales y no hormonales
EsperanzaCastroortig
 
PPTX
cre-lox and cre recombinases in Mouse Genome Informatics (MGI): Module 2
MouseGenomeInformatics
 
PPTX
Animal development
Joe Rineer
 
PPTX
3D cell culture engineering
N Poorin
 
PPTX
stem cells' techniques
Eman Abdelrazik
 
PPTX
Growth and maintenance of cells
Shubham Chinchulkar
 
PPTX
Immune response during bacterial, parasitic and viral infection.pptx
VanshikaVarshney5
 
PDF
Animal cell culture and methodologies
Munira Shahbuddin
 
PPTX
Cell line development
SumedhaBobade
 
PPT
Significance of apoptosis
DEVIKA ANTHARJANAM
 
PPTX
Microfilaments and intermediate filaments
aljeirou
 
PDF
Isolating Chromosomes
deathful
 
PPTX
Ubiquitin & Proteasome: Role in Transcription Regulation
Anjali Dahiya
 
Metodos anticonceptivos hormonales y no hormonales
EsperanzaCastroortig
 
cre-lox and cre recombinases in Mouse Genome Informatics (MGI): Module 2
MouseGenomeInformatics
 
Animal development
Joe Rineer
 
3D cell culture engineering
N Poorin
 
stem cells' techniques
Eman Abdelrazik
 
Growth and maintenance of cells
Shubham Chinchulkar
 
Immune response during bacterial, parasitic and viral infection.pptx
VanshikaVarshney5
 
Animal cell culture and methodologies
Munira Shahbuddin
 
Cell line development
SumedhaBobade
 
Significance of apoptosis
DEVIKA ANTHARJANAM
 
Microfilaments and intermediate filaments
aljeirou
 
Isolating Chromosomes
deathful
 
Ubiquitin & Proteasome: Role in Transcription Regulation
Anjali Dahiya
 
Ad

Similar to Cell cycle... Cell Reproduction (20)

PPT
Sanjay kumar
Sanjay kumar Bhatia
 
PPT
Cell cycle & cell division.htm
Francis Angeles
 
PPT
Cell cycle, Mitosis, Meiosis
subject specialist biology
 
PPTX
Cell Reproduction.pptx
VILLARANTECHRESSYLEA
 
PPT
B.tech biotech i bls u 2.3 cell cycle & cell division(new)
Rai University
 
PPT
Cell division best
Santosh Kumar Kar
 
PPT
Chapter 10
petruccis
 
PPT
Cell Cycle & Cell Division.ppt
hakim hassan
 
PPTX
complete-cell-division.pptxxxxxxxxxxxxxxx
AliceCRivera
 
PPT
cell-cycle-mitosis-meiosis and its application
M. Azizi
 
PPT
cell-cycle-mitosis-meiosis. for all cell
M. Azizi
 
PPT
Bio celldivision-100106220037-phpapp01
Ashraf Shukrat
 
PPSX
Cell cycle & cell division
Alfred Wallace
 
PDF
Mitossis and meosis -cell cycle -
malaika20
 
PPT
Mitosis,Meiosis || PPT
RisTaopa
 
PPTX
High School Biology Cell Cycle & Cell Division
TonyJenkins31
 
PPTX
Cell Cycle & Cell Division.ppt.pptx
HappySharma52
 
PDF
cell cycle and control checkpoints throght cyclin cdk complex
lamiakandil2
 
PPT
The Cell Cycle Mitosis 2015
Dobbs Ferry High School
 
PPT
Mitosis and Cell Cycle Control (Cell Biology).ppt
NABIHANAEEM2
 
Sanjay kumar
Sanjay kumar Bhatia
 
Cell cycle & cell division.htm
Francis Angeles
 
Cell cycle, Mitosis, Meiosis
subject specialist biology
 
Cell Reproduction.pptx
VILLARANTECHRESSYLEA
 
B.tech biotech i bls u 2.3 cell cycle & cell division(new)
Rai University
 
Cell division best
Santosh Kumar Kar
 
Chapter 10
petruccis
 
Cell Cycle & Cell Division.ppt
hakim hassan
 
complete-cell-division.pptxxxxxxxxxxxxxxx
AliceCRivera
 
cell-cycle-mitosis-meiosis and its application
M. Azizi
 
cell-cycle-mitosis-meiosis. for all cell
M. Azizi
 
Bio celldivision-100106220037-phpapp01
Ashraf Shukrat
 
Cell cycle & cell division
Alfred Wallace
 
Mitossis and meosis -cell cycle -
malaika20
 
Mitosis,Meiosis || PPT
RisTaopa
 
High School Biology Cell Cycle & Cell Division
TonyJenkins31
 
Cell Cycle & Cell Division.ppt.pptx
HappySharma52
 
cell cycle and control checkpoints throght cyclin cdk complex
lamiakandil2
 
The Cell Cycle Mitosis 2015
Dobbs Ferry High School
 
Mitosis and Cell Cycle Control (Cell Biology).ppt
NABIHANAEEM2
 
Ad

More from Microbiology (20)

PPTX
7 food hygiene, sanitation legislation
Microbiology
 
PDF
Immune Response to HIV Infection
Microbiology
 
PDF
The T-Cell Antigen Receptor Complex
Microbiology
 
PDF
T-cell activation
Microbiology
 
PDF
MHC-I, MHC-II & MHC-III
Microbiology
 
PDF
Processing and presentation mid
Microbiology
 
PPTX
Food preservation in warm countries
Microbiology
 
DOCX
Extinction
Microbiology
 
DOCX
Exsitu and in situ conservation
Microbiology
 
DOCX
Microbial Evolution
Microbiology
 
DOCX
Loss of genetic diversity
Microbiology
 
DOCX
Gene environment interaction
Microbiology
 
DOCX
How to store food in hot
Microbiology
 
DOCX
IUPAC naming and formulae
Microbiology
 
DOCX
Basic iupac organic nomenclature
Microbiology
 
DOCX
Geometry of hybridiztion
Microbiology
 
DOCX
Hybridization
Microbiology
 
DOCX
Why Firefly give light during night?
Microbiology
 
PPTX
OXYGEN CYCLE
Microbiology
 
DOCX
billion tree tsunami
Microbiology
 
7 food hygiene, sanitation legislation
Microbiology
 
Immune Response to HIV Infection
Microbiology
 
The T-Cell Antigen Receptor Complex
Microbiology
 
T-cell activation
Microbiology
 
MHC-I, MHC-II & MHC-III
Microbiology
 
Processing and presentation mid
Microbiology
 
Food preservation in warm countries
Microbiology
 
Extinction
Microbiology
 
Exsitu and in situ conservation
Microbiology
 
Microbial Evolution
Microbiology
 
Loss of genetic diversity
Microbiology
 
Gene environment interaction
Microbiology
 
How to store food in hot
Microbiology
 
IUPAC naming and formulae
Microbiology
 
Basic iupac organic nomenclature
Microbiology
 
Geometry of hybridiztion
Microbiology
 
Hybridization
Microbiology
 
Why Firefly give light during night?
Microbiology
 
OXYGEN CYCLE
Microbiology
 
billion tree tsunami
Microbiology
 

Recently uploaded (20)

PPTX
What’s under the hood: Parsing standardized learning content for AI
Rustici Software
 
PPTX
Education and Perspectives of Education.pptx
Central University of South Bihar, Gaya, Bihar
 
PDF
LIFE & LIVING TRILOGY - PART (3) REALITY & MYSTERY.pdf
sureshkumarsoni26
 
PDF
Empowerment Technology for Senior High School Guide
solthereseamericandr
 
PDF
Literature_Review_methods_ BRACU_MKT426 course material
mokoto4834
 
PDF
semiconductor packaging in vlsi design fab
KarpoorasundariK
 
PPTX
A powerpoint presentation on the Revised K-10 Science Shaping Paper
JericEstaco2
 
PDF
My India Quiz Book_20210205121199924.pdf
AtandraDey2
 
PDF
Climate and Adaptation MCQs class 7 from chatgpt
AkashDTejwani
 
PDF
LIFE & LIVING TRILOGY - PART - (2) THE PURPOSE OF LIFE.pdf
sureshkumarsoni26
 
PPTX
Core Concepts of Personalized Learning and Virtual Learning Environments
Dr. Bushra Sumaiya
 
PPTX
Computer Architecture Input Output Memory.pptx
Gunasundari Selvaraj
 
PDF
FORM 1 BIOLOGY MIND MAPS and their schemes
arcade5
 
PDF
Race Reva University – Shaping Future Leaders in Artificial Intelligence
RACE REVA University
 
PDF
BP 505 T. PHARMACEUTICAL JURISPRUDENCE (UNIT 1).pdf
CMEmpire
 
PDF
MBA _Common_ 2nd year Syllabus _2021-22_.pdf
DrAnubha4
 
PDF
IP : I ; Unit I : Preformulation Studies
RAGHUNATH SAKHARE
 
PDF
Vision Prelims GS PYQ Analysis 2011-2022 www.upscpdf.com.pdf
navneetgupta711851
 
PDF
HVAC Specification 2024 according to central public works department
amitrobanipl
 
PDF
Hazard Identification & Risk Assessment .pdf
estagiarioprotegesms
 
What’s under the hood: Parsing standardized learning content for AI
Rustici Software
 
Education and Perspectives of Education.pptx
Central University of South Bihar, Gaya, Bihar
 
LIFE & LIVING TRILOGY - PART (3) REALITY & MYSTERY.pdf
sureshkumarsoni26
 
Empowerment Technology for Senior High School Guide
solthereseamericandr
 
Literature_Review_methods_ BRACU_MKT426 course material
mokoto4834
 
semiconductor packaging in vlsi design fab
KarpoorasundariK
 
A powerpoint presentation on the Revised K-10 Science Shaping Paper
JericEstaco2
 
My India Quiz Book_20210205121199924.pdf
AtandraDey2
 
Climate and Adaptation MCQs class 7 from chatgpt
AkashDTejwani
 
LIFE & LIVING TRILOGY - PART - (2) THE PURPOSE OF LIFE.pdf
sureshkumarsoni26
 
Core Concepts of Personalized Learning and Virtual Learning Environments
Dr. Bushra Sumaiya
 
Computer Architecture Input Output Memory.pptx
Gunasundari Selvaraj
 
FORM 1 BIOLOGY MIND MAPS and their schemes
arcade5
 
Race Reva University – Shaping Future Leaders in Artificial Intelligence
RACE REVA University
 
BP 505 T. PHARMACEUTICAL JURISPRUDENCE (UNIT 1).pdf
CMEmpire
 
MBA _Common_ 2nd year Syllabus _2021-22_.pdf
DrAnubha4
 
IP : I ; Unit I : Preformulation Studies
RAGHUNATH SAKHARE
 
Vision Prelims GS PYQ Analysis 2011-2022 www.upscpdf.com.pdf
navneetgupta711851
 
HVAC Specification 2024 according to central public works department
amitrobanipl
 
Hazard Identification & Risk Assessment .pdf
estagiarioprotegesms
 

Cell cycle... Cell Reproduction

  • 1. 1
  • 2. ASSIGNMENT # 03 • Prepared by Amjad Khan • Submitted to Dear, Sir Ghadir Ali • Program BS Microbiology 3th • Subject CELL BIOLOGY • Topic CELL CYCLE • Date 12th January, 2015 2
  • 4. 4 TypES of CEllTypES of CEll REpRoduCTIoNREpRoduCTIoNAsexual reproductionAsexual reproduction involves ainvolves a single cellsingle cell dividing to makedividing to make 2 new,2 new, identical daughter cellsidentical daughter cells Mitosis & binary fissionMitosis & binary fission areare examples of asexual reproductionexamples of asexual reproduction Sexual reproductionSexual reproduction involves twoinvolves two cells (egg & sperm) joining to make acells (egg & sperm) joining to make a new cell (zygote)new cell (zygote) that isthat is NOTNOT identical to the original cellsidentical to the original cells MeiosisMeiosis is an exampleis an example
  • 5. Division Mechanisms Prokaryotic organisms – Binary fission Eukaryotic organisms – Mitosis • Karyokinesis (division of nucleus) • Cytokinesis (division of cytoplasm) – Meiosis
  • 6. 6 CEll dIvISIoN INCEll dIvISIoN IN pRokARyoTESpRokARyoTES
  • 7. 7 Cell Division in ProkaryotesCell Division in Prokaryotes  Prokaryotes such asProkaryotes such as bacteriabacteria divide into 2divide into 2 identical cells by theidentical cells by the process ofprocess of binarybinary fissionfission  Single chromosomeSingle chromosome makes a copy ofmakes a copy of itselfitself  Cell wall formsCell wall forms between thebetween the chromosomes dividingchromosomes dividing the cellthe cell ParentParent cellcell 2 identical daughter cells2 identical daughter cells ChromosomeChromosome doublesdoubles Cell splitsCell splits
  • 8. 8 Prokaryotic CellProkaryotic Cell Undergoing Binary FissionUndergoing Binary Fission
  • 9. 9 Animation of Binary FissionAnimation of Binary Fission
  • 11. 11 Five Phases of the Cell CycleFive Phases of the Cell Cycle GG11 - primary growth/gap phase- primary growth/gap phase S – synthesis; DNA replicatedS – synthesis; DNA replicated GG22 - secondary growth/gap- secondary growth/gap phasephase collectively these 3 stages arecollectively these 3 stages are calledcalled interphaseinterphase M - mitosisM - mitosis C - cytokinesisC - cytokinesis
  • 13. 13 Interphase - GInterphase - G11 StageStage 11stst growth/gap stagegrowth/gap stage after cellafter cell divisiondivision CellsCells maturemature by making moreby making more cytoplasm & organellescytoplasm & organelles Cell carries on itsCell carries on its normalnormal metabolic activitiesmetabolic activities i.e.i.e. respiration, digestion etc.respiration, digestion etc.
  • 14. 14 Interphase – S StageInterphase – S Stage SynthesisSynthesis stagestage DNADNA is copied oris copied or replicatedreplicated TwoTwo identicalidentical copiescopies of DNAof DNA OriginalOriginal DNADNA
  • 15. 15 Interphase – GInterphase – G22 StageStage 22ndnd Growth/GapGrowth/Gap StageStage OccursOccurs after DNA has been copie;after DNA has been copie; also in preparation for M phasealso in preparation for M phase All cellAll cell structures needed forstructures needed for divisiondivision are made (e.g. centrioles)are made (e.g. centrioles) BothBoth organelles & proteinsorganelles & proteins areare synthesizedsynthesized
  • 16. 16 What’s Happening in Interphase?What’s Happening in Interphase? What the cell looks likeWhat the cell looks like Animal Cell What’s occurring
  • 17. 17 Sketch the Cell CycleSketch the Cell Cycle DaughterDaughter CellsCells DNA CopiedDNA Copied CellsCells MatureMature Cells prepare forCells prepare for DivisionDivision Cell Divides intoCell Divides into Identical cellsIdentical cells
  • 19. 19 MitosisMitosis Division of theDivision of the nucleusnucleus (karyokinesis)(karyokinesis) Division of theDivision of the cytoplasmcytoplasm (cytokinesis)(cytokinesis) Only occurs inOnly occurs in eukaryoteseukaryotes HasHas fourfour stagesstages Doesn’t occur inDoesn’t occur in some cells such assome cells such as brain cellsbrain cells
  • 20. 20 Four Mitotic StagesFour Mitotic Stages ProProphasephase MetaMetaphasephase AnaAnaphasephase TeloTelophasephase
  • 21. 21 Early ProphaseEarly Prophase ChromatinChromatin in nucleus condenses toin nucleus condenses to formform visible chromosomesvisible chromosomes Mitotic spindleMitotic spindle forms from fibers informs from fibers in cytoskeleton orcytoskeleton or centrioles (animal)centrioles (animal) ChromosomesChromosomes NucleolusNucleolus CytoplasmCytoplasm Nuclear MembraneNuclear Membrane
  • 22. 22 Late ProphaseLate Prophase Nuclear membrane & nucleolusNuclear membrane & nucleolus areare broken downbroken down ChromosomesChromosomes continue condensing &continue condensing & areare clearly visibleclearly visible Spindle fibers calledSpindle fibers called kinetochoreskinetochores attach to the centromereattach to the centromere of eachof each chromosomechromosome SpindleSpindle finishes forming between thefinishes forming between the poles of the cellpoles of the cell
  • 23. 23 Late ProphaseLate Prophase Nucleus & Nucleolus have disintegratedNucleus & Nucleolus have disintegrated ChromosomesChromosomes
  • 24. 24 Spindle Fiber attached toSpindle Fiber attached to ChromosomeChromosome Kinetochore FiberKinetochore Fiber ChromosomeChromosome
  • 25. 25 Review of ProphaseReview of Prophase What the cellWhat the cell looks likelooks like What’s happeningWhat’s happening
  • 26. 26 Spindle FibersSpindle Fibers The mitoticThe mitotic spindlespindle form from theform from the microtubulesmicrotubules in plantsin plants andand centriolescentrioles in animal cellsin animal cells Polar fibersPolar fibers extend from one pole ofextend from one pole of the cell to the opposite polethe cell to the opposite pole Kinetochore fibersKinetochore fibers extend from theextend from the pole to the centromere of thepole to the centromere of the chromosome to which they attachchromosome to which they attach AstersAsters are short fibers radiatingare short fibers radiating from centriolesfrom centrioles
  • 28. 28 MetaphaseMetaphase Chromosomes, attached to theChromosomes, attached to the kinetochore fiberskinetochore fibers, move to the center, move to the center of the cellof the cell Chromosomes are now lined up at theChromosomes are now lined up at the equatorequator Pole ofPole of the Cellthe Cell Equator of CellEquator of Cell
  • 30. 30 Review of MetaphaseReview of Metaphase What the cell looksWhat the cell looks likelike What’sWhat’s occurringoccurring
  • 31. 31 AnaphaseAnaphase OccursOccurs rapidlyrapidly SisterSister chromatidschromatids areare pulled apart topulled apart to opposite polesopposite poles of the cell byof the cell by kinetochorekinetochore fibersfibers
  • 32. 32 Anaphase ReviewAnaphase Review What theWhat the cell lookscell looks likelike What’sWhat’s occurringoccurring
  • 33. 33 TelophaseTelophase Sister chromatids atSister chromatids at oppositeopposite polespoles SpindleSpindle disassemblesdisassembles Nuclear envelopeNuclear envelope forms aroundforms around each set of sister chromatidseach set of sister chromatids NucleolusNucleolus reappearsreappears CYTOKINESISCYTOKINESIS occursoccurs Chromosomes reappear asChromosomes reappear as chromatinchromatin
  • 34. 34 Comparison of Anaphase & TelophaseComparison of Anaphase & Telophase
  • 35. 35 CytokinesisCytokinesis Means division of the cytoplasmMeans division of the cytoplasm DivisionDivision of cell into two,of cell into two, identical halves calledidentical halves called daughterdaughter cellscells In plant cells, cell plateIn plant cells, cell plate formsforms at the equator to divide cellat the equator to divide cell In animal cells,In animal cells, cleavage furrowcleavage furrow forms to split cellforms to split cell
  • 36. 36 CytokinesisCytokinesis Cleavage furrowCleavage furrow in animal cellin animal cell Cell plate inCell plate in animal cellanimal cell
  • 38. 38 Daughter Cells of MitosisDaughter Cells of Mitosis Have theHave the same number ofsame number of chromosomes as each otherchromosomes as each other and asand as the parent cellthe parent cell from which theyfrom which they were formedwere formed IdenticalIdentical to each other, butto each other, but smallersmaller than parent cellthan parent cell MustMust grow in sizegrow in size to become matureto become mature cellscells (G(G11 of Interphase)of Interphase)
  • 39. 39 Identical Daughter CellsIdentical Daughter Cells Chromosome number theChromosome number the samesame, but cells, but cells smallersmaller than parent cellthan parent cell What isWhat is the 2nthe 2n oror diploiddiploid number?number? 22
  • 41. 41 Draw & Learn these StagesDraw & Learn these Stages
  • 42. 42 Draw & Learn these StagesDraw & Learn these Stages
  • 43. 43 InterphaseInterphase ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase Name the Mitotic Stages:Name the Mitotic Stages: Name this?Name this? Name this?Name this?
  • 44. 44 Eukaryotic Cell DivisionEukaryotic Cell Division  Used forUsed for growth andgrowth and repairrepair  Produce two new cellsProduce two new cells identical to the originalidentical to the original cellcell  Cells areCells are diploid (2n)diploid (2n) Chromosomes duringChromosomes during Metaphase of mitosisMetaphase of mitosis ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase CytokinesisCytokinesis
  • 45. 45 Mitosis AnimationMitosis Animation Name each stage as you see it occur?Name each stage as you see it occur?
  • 46. 46 Mitosis in Onion Root TipsMitosis in Onion Root Tips Do you see any stages of mitosis?Do you see any stages of mitosis?
  • 47. 47 Locate the Four MitoticLocate the Four Mitotic Stages in PlantsStages in Plants MetaphaseMetaphase ProphaseProphase AnaphaseAnaphase TelophaseTelophase
  • 48. 48 Uncontrolled Mitosis  If mitosis is notIf mitosis is not controlledcontrolled, unlimited, unlimited cell division occurscell division occurs causing cancerouscausing cancerous tumorstumors  OncogenesOncogenes are specialare special proteinsproteins that increase the chanceincrease the chance that a normal cellthat a normal cell develops into adevelops into a tumortumor cellcell Cancer cellsCancer cells
  • 49. 49 MeiosisMeiosis Formation of GametesFormation of Gametes (Eggs & Sperm)(Eggs & Sperm)
  • 50. Words to knoW Gametes - reproductive cells that unite during sexual reproduction to form a new cell called a zygote (male = sperm, female = egg cell) Germ cells – sperm or egg cells Somatic cells - any cell other than the reproductive cells Diploid - a cell that contains two sets of chromosomes (2n), as normally found in somatic cells Haploid - have one set of chromosomes (n=1) as in germ cells, or half as many as a somatic cell Homologous – chromosomes that are alike in structure and genes Alleles – different forms of a gene ex. if talking about hair color as the gene, different alleles would be different colors like red, blonde, black etc. 50
  • 51. 51 Facts About MeiosisFacts About Meiosis Preceded by interphase whichPreceded by interphase which includesincludes chromosome replicationchromosome replication TwoTwo meiotic divisions:meiotic divisions: Meiosis IMeiosis I and Meiosis IIand Meiosis II AkaAka reduction-divisionreduction-division Original cell is diploid (2n)Original cell is diploid (2n) Four daughter cellsFour daughter cells produced thatproduced that areare haploid (n)haploid (n)
  • 52. 52 Facts About MeiosisFacts About Meiosis Daughter cellsDaughter cells contain half the numbercontain half the number of chromosomesof chromosomes as the original cellas the original cell ProducesProduces gametesgametes (eggs & sperm(eggs & sperm)) Occurs in theOccurs in the testestestes in malesin males ((SpermatogenesisSpermatogenesis)) Occurs in theOccurs in the ovariesovaries in femalesin females ((OogenesisOogenesis)) Human diploid cells haveHuman diploid cells have 46 chromosomes46 chromosomes (2n=46)(2n=46) Human sperm and egg cells haveHuman sperm and egg cells have 2323 chromosomes (n=23) eachchromosomes (n=23) each
  • 53. 53  Start withStart with 46 double stranded46 double stranded chromosomes (2n)chromosomes (2n) After 1 division -After 1 division - 23 double23 double stranded chromosomes (n)stranded chromosomes (n) After 2nd division -After 2nd division - 23 single23 single stranded chromosomes (n)stranded chromosomes (n)  Occurs in ourOccurs in our germ cellsgerm cells More Meiosis FactsMore Meiosis Facts
  • 54. 54 Why Do we Need Meiosis?Why Do we Need Meiosis? It is the fundamental basis ofIt is the fundamental basis of sexual reproductionsexual reproduction Two haploid (1n) gametes areTwo haploid (1n) gametes are brought together throughbrought together through fertilizationfertilization to form a diploidto form a diploid (2n) zygote(2n) zygote
  • 55. 55 Fertilization – “Putting itFertilization – “Putting it all together”all together” 1n =31n =3 2n = 62n = 6
  • 56. 56 Replication of ChromosomesReplication of Chromosomes ReplicationReplication is theis the process ofprocess of duplicating aduplicating a chromosomechromosome OccursOccurs prior toprior to divisiondivision Replicated copiesReplicated copies are calledare called sistersister chromatidschromatids Held together atHeld together at centromerecentromere Occurs inOccurs in InterphaseInterphase
  • 57. 57 A Replicated ChromosomeA Replicated Chromosome HomologuesHomologues (same genes,(same genes, different alleles)different alleles) SisterSister ChromatidsChromatids (same genes,(same genes, same alleles)same alleles) Gene XGene X Homologues separate in meiosis I andHomologues separate in meiosis I and therefore different alleles separate.therefore different alleles separate.
  • 58. 58 Meiosis Forms Haploid GametesMeiosis Forms Haploid Gametes  Meiosis mustMeiosis must reduce the chromosome numberreduce the chromosome number by halfby half  Fertilization then restoresFertilization then restores the 2n numberthe 2n number from mom from dad child meiosis reduces genetic content too much! The right number!
  • 59. 59 Meiosis: Two Part CellMeiosis: Two Part Cell DivisionDivision HomologuesHomologues separateseparate SisterSister chromatidschromatids separateseparate DiploidDiploid MeiosisMeiosis II MeiosisMeiosis IIII DiploidDiploid HaploidHaploid
  • 60. 60 Meiosis I: Reduction DivisionMeiosis I: Reduction Division NucleusNucleus SpindleSpindle fibersfibers NuclearNuclear envelopeenvelopeEarlyEarly Prophase IProphase I (Chromosome(Chromosome numbernumber doubleddoubled)) LateLate ProphaseProphase II MetaphaseMetaphase II AnaphaseAnaphase II Telophase ITelophase I (diploid)(diploid)
  • 61. 61 Prophase IProphase I Early prophaseEarly prophase HomologuesHomologues pair.pair. Crossing overCrossing over occursoccurs. Late prophaseLate prophase Chromosomes condense.Chromosomes condense. Spindle forms.Spindle forms. Nuclear envelopeNuclear envelope fragments.fragments.
  • 62. 62 Tetrads Form in Prophase ITetrads Form in Prophase I Homologous chromosomesHomologous chromosomes (each with sister chromatids)(each with sister chromatids) Join to form aJoin to form a TETRADTETRAD Called SynapsisCalled Synapsis
  • 63. 63 Crossing-OverCrossing-Over  HomologousHomologous chromosomeschromosomes in ain a tetradtetrad cross overcross over each othereach other  Pieces ofPieces of chromosomes orchromosomes or genes aregenes are exchangedexchanged  ProducesProduces GeneticGenetic recombinationrecombination inin the offspringthe offspring •Occurs in nonsister chromatids •Increases genetic variability Genetic recombination in which a strand of the genetic material (DNA/RNA)is broken and then joined to the end of a different DNA molecule.
  • 64. 64 Homologous ChromosomesHomologous Chromosomes During Crossing-OverDuring Crossing-Over
  • 65. 65 Crossing-over multiplies the already hugeCrossing-over multiplies the already huge number of different gamete typesnumber of different gamete types produced by independent assortmentproduced by independent assortment Crossing-OverCrossing-Over
  • 66. 66 Metaphase IMetaphase I Homologous pairsHomologous pairs of chromosomesof chromosomes align along thealign along the equatorequator of theof the cellcell
  • 67. 67 Anaphase IAnaphase I Homologues separateHomologues separate andand move to opposite poles.move to opposite poles. Sister chromatidsSister chromatids remainremain attachedattached at theirat their centromerescentromeres.
  • 68. 68 Telophase ITelophase I Nuclear envelopesNuclear envelopes reassemble.reassemble. Spindle disappears.Spindle disappears. CytokinesisCytokinesis divides celldivides cell into two.into two.
  • 69. 69 Meiosis IIMeiosis II Only one homologue of eachOnly one homologue of each chromosome is present inchromosome is present in the cellthe cell. Meiosis II produces gametes withMeiosis II produces gametes with one copy of each chromosome andone copy of each chromosome and thus one copy of each gene.thus one copy of each gene. Sister chromatids carrySister chromatids carry identical geneticidentical genetic informationinformation.. Gene XGene X
  • 70. 70 Meiosis II: ReducingMeiosis II: Reducing Chromosome NumberChromosome Number ProphaseProphase IIII MetaphaseMetaphase IIII AnaphaseAnaphase IIII TelophaseTelophase IIII 4 Identical4 Identical haploid cellshaploid cells
  • 71. 71 Prophase IIProphase II Nuclear envelopeNuclear envelope fragments.fragments. Spindle forms.Spindle forms.
  • 72. 72 Metaphase IIMetaphase II Chromosomes alignChromosomes align alongalong equatorequator of cellof cell..
  • 73. 73 Anaphase IIAnaphase II Sister chromatidsSister chromatids separate andseparate and move tomove to oppositeopposite polespoles. EquatorEquator PolePole
  • 74. 74 Telophase IITelophase II Nuclear envelopeNuclear envelope assembles.assembles. ChromosomesChromosomes decondense.decondense. Spindle disappears.Spindle disappears. Cytokinesis dividesCytokinesis divides cell into two.cell into two.
  • 75. 75 Results of MeiosisResults of Meiosis Gametes (egg & sperm)Gametes (egg & sperm) formform Four haploid cells withFour haploid cells with one copy of eachone copy of each chromosomechromosome One allele of each geneOne allele of each gene Different combinations ofDifferent combinations of alleles for differentalleles for different genes along thegenes along the chromosomechromosome
  • 77. 77 SpermatogenesisSpermatogenesis Occurs in theOccurs in the testestestes Two divisionsTwo divisions produce 4produce 4 spermatidsspermatids SpermatidsSpermatids maturemature into sperminto sperm Men produce aboutMen produce about 250,000,000250,000,000 sperm per daysperm per day
  • 78. 78 Spermatogenesis in theSpermatogenesis in the TestesTestes SpermatidSpermatid
  • 80. 80 OogenesisOogenesis Occurs in theOccurs in the ovariesovaries Two divisions produceTwo divisions produce 3 polar bodies3 polar bodies that die andthat die and 1 egg1 egg Polar bodies die because ofPolar bodies die because of unequalunequal division of cytoplasmdivision of cytoplasm Immature egg calledImmature egg called oocyteoocyte Starting at puberty, one oocyteStarting at puberty, one oocyte matures into anmatures into an ovum (egg)ovum (egg) every 28every 28 daysdays
  • 81. 81 Oogenesis in the OvariesOogenesis in the Ovaries
  • 82. 82 OogenesisOogenesis OogoniumOogonium (diploid)(diploid) MitosisMitosis PrimaryPrimary oocyteoocyte (diploid)(diploid) Meiosis IMeiosis I SecondarySecondary oocyteoocyte (haploid)(haploid) Meiosis IIMeiosis II (if fertilization(if fertilization occurs)occurs) First polar bodyFirst polar body may dividemay divide (haploid)(haploid) PolarPolar bodiesbodies diedie Ovum (egg)Ovum (egg) SecondSecond polar bodypolar body (haploid)(haploid) a A X X a X A X a X a X MatureMature eggegg A X A X
  • 84. 84 MitosisMitosis MeiosisMeiosis Number ofNumber of divisionsdivisions 11 22 Number ofNumber of daughter cellsdaughter cells 22 44 GeneticallyGenetically identical?identical? YesYes NoNo Chromosome #Chromosome # Same as parentSame as parent Half of parentHalf of parent WhereWhere Somatic cellsSomatic cells Reproductive cellsReproductive cells WhenWhen Throughout lifeThroughout life At sexual maturityAt sexual maturity RoleRole Growth andGrowth and repairrepair Sexual reproductionSexual reproduction Comparison of DivisionsComparison of Divisions
  • 85. 85 Meiosis Mitosis Definition: A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes in a diploid cell. A process of asexual reproduction in which the cell divides in two producing a replica, with an equal number of chromosomes in haploid cell Function: sexual reproduction Cellular Reproduction & general growth and repair of the body Type of Reproduction: Sexual Asexual Occurs in: Humans, animals, plants, fungi all organisms Genetically: different identical Crossing Over: Yes, mixing of chromosomes can occur. No, crossing over cannot occur. Pairing of Homologues: Yes No Number of Divisions: 2 1 Number of Haploid Daughter Cells produced: 4 2 Chromosome Number: Reduced by half Remains the same Steps: The steps of meiosis are Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II and Telophase II. The steps of mitosis are Interphase, Prophase, Metaphase, Anaphase, Telophase and Cytokinesis Karyokenesis: Occurs in Interphase I Occurs in Interphase Cytokenesis: Occurs in Telophase I & Telohpase II Occurs in Telophase Centromeres Split: The centromeres do not separate during anaphase I, but during anaphase II The centromeres split during Anaphase Creates: Sex cells only: Female egg cells or Makes everything other than sex

Editor's Notes

  • #57: Replication is the process of duplicating chromosome. The new copy of a chromosome is formed by DNA synthesis during S-phase. The chromosome copies are called sister chromatids. Sister chromatids are held together at the centromere.