Post on 05-Jan-2016
Chapter 11Chapter 11
Continuity of Life:Continuity of Life:
Cellular ReproductionCellular Reproduction
Chapter 11 2
Binary FissionBinary Fission
DNA replicated
Membrane added
Chapter 11 3
Binary Fission 2Binary Fission 2
constriction
fission
Chapter 11 4
False-Color EMFalse-Color EMof Dividing Bacteriumof Dividing Bacterium
Division planeDivision plane
Cell wallCell wall
CytoplasmCytoplasm
NuclearNuclearmaterialmaterial
Chapter 11 5
Mitotic Mitotic
cell cell divisiondivision
Mitotic Mitotic cell cell division & division &
differ-differ-entiationentiation
Functions of MitosisFunctions of Mitosis
TissuesTissues
OrgansOrgansFertilized eggFertilized egg(zygote)(zygote) Multicell stageMulticell stage
Chapter 11 6
Protozoa:Protozoa:Asexual Reproduction by MitosisAsexual Reproduction by Mitosis
New individualsNew individuals
Chapter 11 7
Yeasts:Yeasts:Asexual Reproduction by MitosisAsexual Reproduction by Mitosis
BuddingBuddingNucleus divides by Nucleus divides by
mitosismitosisBud forms on cellBud forms on cellNucleus moves into Nucleus moves into
budbudBud separatesBud separates
Chapter 11 8
Hydra:Hydra:Asexual Reproduction by MitosisAsexual Reproduction by Mitosis
Chapter 11 9
GeneticallyGeneticallyIdentical Aspen GrovesIdentical Aspen Groves
Three separate aspen Three separate aspen grovesgroves
Each produced Each produced asexually from single asexually from single ancestorancestor
Variable between Variable between grovesgroves
Identical within grovesIdentical within groves
Trees Trees synchronously synchronously
lost leaveslost leaves
Trees Trees synchronously synchronously
lost leaveslost leaves
Trees Trees synchronously synchronously turned yellowturned yellow
Trees Trees synchronously synchronously turned yellowturned yellow
Trees still Trees still greengreen
Trees still Trees still greengreen
Chapter 11 10
Mitosis, Meiosis,Mitosis, Meiosis,and the Sexual Cycleand the Sexual Cycle
Chapter 11 11
11 single-stranded chromosomesingle-stranded chromosome22 double helixdouble helix
uncondenseduncondensed
DNA replicationDNA replication
11 double-stranded chromosomedouble-stranded chromosome22 double helicesdouble helices
still uncondensedstill uncondensed
Chromosome Chromosome condensationcondensation
11 double-stranded chromosomedouble-stranded chromosome22 double helicesdouble helices
now condensednow condensed
centromere centromere aachromatidchromatid
cellcell basebasepairspairs
closer lookstill closer lookeven closer look
Chromosome CondensationChromosome Condensation
Chapter 11 12
HumanHumanChromosomes during MitosisChromosomes during Mitosis
Chapter 11 13
Human Karyotype, MaleHuman Karyotype, Male
These are These are chromosomes from chromosomes from mitosismitosis
Stained to show Stained to show regionsregions
Numbered by lengthNumbered by lengthOccur in pairsOccur in pairs
Chapter 11 14
telophase
metaphase
anaphase
cell
divi
sion
GG00: nondividing: nondividing
interphaseinterphase
The EukaryoticThe EukaryoticCell CycleCell Cycle
S: Synthesis S: Synthesis of DNA; of DNA; chromosomes chromosomes duplicatedduplicated
GG11: Growth: Growth
GG22: Growth: Growth
prophase
cytokinesis
Mito
sis
Chapter 11 15
Interphase : The chromosomes (blue) are in the thin, extended state and appear as a mass in the center of the cell. The microtubules (red) extend outward from the nucleus to all parts of the cell.
Metaphase: The chromosomes have moved along the spindle microtubules to the equator of the cell.
Late prophase: Chromosomes (blue) have condensed and attached to microtubules of spindle fibers (red). Microtubules have reorganized to form the spindle; chromosomes, now condensed, are clearly visible.
Phases of Mitosis, 1Phases of Mitosis, 1
Chapter 11 16
Separation of Sister ChromatidsSeparation of Sister Chromatids
In metaphase, sister chromatids In metaphase, sister chromatids are held together at centromereare held together at centromere
At end of metaphase, centromere At end of metaphase, centromere releases sister chromatidsreleases sister chromatids
In anaphase, they move to opposite In anaphase, they move to opposite polespoles
In metaphase, sister chromatids In metaphase, sister chromatids are held together at centromereare held together at centromere
At end of metaphase, centromere At end of metaphase, centromere releases sister chromatidsreleases sister chromatids
In anaphase, they move to opposite In anaphase, they move to opposite polespoles
Chapter 11 17
Anaphase: Sister chromatids have separated, and one set of chromosomes moves along the spindle microtubule to each pole of the cell.
Telophase: The chromosomes have gathered into two clusters, one at the site of each future nucleus.
Next interphase: Chromosomes are relaxing again into their extended state. Spindle fibers are disappearing, and the microtubules of the 2 daughter cells rearrange into the interphase pattern.
Phases of Mitosis, 2Phases of Mitosis, 2
Chapter 11 18
Mitosis:Mitosis:Prophase - MetaphaseProphase - Metaphase
Kinetochores align at cell’s
equator
Nucleolus disappears;
Nuclear envelope breaks down
Microtubules attach to
kinetochores
Chromosomes condense and
shorten
Centrioles begin to move apart;Spindle forms
Duplicated chromosomes
remain elongated
Centrioles have also been duplicated
LateLateInterphaseInterphase
EarlyEarlyProphaseProphase
LateLateProphaseProphase MetaphaseMetaphase
Chapter 11 19
MitosisMitosisAnaphase - CytokinesisAnaphase - Cytokinesis
Free spindle fibers push poles apart
Chromatids become
independent chromosomes
One set of chromosomes;
Begin unwinding
Nuclear envelope re-
forms
Cytoplasm divided along
equator
Each daughter gets 1 nucleus &
half of cytoplasm
Spindle disappears; Nucleolus reappears
AnaphaseAnaphase TelophaseTelophase CytokinesisCytokinesisNextNext
InterphaseInterphase
Chapter 11 20
Cytokinesis of a Ciliated CellCytokinesis of a Ciliated Cell
Cleavage FurrowCleavage Furrow
Daughter CellsDaughter Cells
Chapter 11 21
Cytokinesis in PlantsCytokinesis in Plants
Vesicles fuse to form cell wall
and membranesComplete
separation of daughter cells
Chapter 11 22
Meiosis IMeiosis IHomologous
chromosomes pair and cross over
Homologous chromosomes
exchange DNA & align on equator
Homologous chromosomes move to
opposite poles
Prophase IProphase I Metaphase IMetaphase I Anaphase IAnaphase I Telophase ITelophase I
Chapter 11 23
Meiosis IIMeiosis II
Prophase IIProphase II Metaphase IIMetaphase II Anaphase IIAnaphase II Telophase IITelophase IIFourFour
HaploidHaploidCellsCells
Similar to MitosisSimilar to Mitosis
Chapter 11 24
Crossing OverCrossing Over
Homologues Homologues pair uppair up
Protein strands Protein strands zip togetherzip together
Recombination Recombination enzymes snip enzymes snip and rejoin and rejoin DNADNA
Homologs Homologs separate with separate with new gene new gene combinationscombinations
Chapter 11 25 Meiosis vs. Mitosis:Meiosis vs. Mitosis:
Comparison of SpindlesComparison of SpindlesMeiosis: Duplicated chromosomes Meiosis: Duplicated chromosomes with one kinetochore; Paired with one kinetochore; Paired homologues go to opposite poles.homologues go to opposite poles.
Meiosis: Duplicated chromosomes Meiosis: Duplicated chromosomes with one kinetochore; Paired with one kinetochore; Paired homologues go to opposite poles.homologues go to opposite poles.
Mitosis: Duplicated chromosomes Mitosis: Duplicated chromosomes with two kinetochores; Unpaired with two kinetochores; Unpaired homologs split between sister homologs split between sister chromatids, which go to opposite chromatids, which go to opposite poles.poles.
Mitosis: Duplicated chromosomes Mitosis: Duplicated chromosomes with two kinetochores; Unpaired with two kinetochores; Unpaired homologs split between sister homologs split between sister chromatids, which go to opposite chromatids, which go to opposite poles.poles.
Chapter 11 26 Meiosis vs. Mitosis:Meiosis vs. Mitosis:
Comparison of StagesComparison of Stages
Chapter 11 27
Metaphase Alignment ScenariosMetaphase Alignment Scenarios
Chapter 11Chapter 11
The endThe end