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Sexual Reproduction. Cellular Reproduction. There are 2 types of reproduction: Asexual Reproduction Sexual Reproduction. Cellular Reproduction. Asexual Reproduction (5 phases) 1 mother cell divides into 2 daughter cells Daughter cell is identi cal to its mother - PowerPoint PPT Presentation
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Sexual Sexual ReproductionReproduction
Cellular ReproductionCellular Reproduction
There are 2 types ofThere are 2 types of reproduction: reproduction:
Asexual ReproductionAsexual Reproduction
Sexual ReproductionSexual Reproduction
Cellular ReproductionCellular Reproduction
1.1. Asexual Reproduction (5 phases)Asexual Reproduction (5 phases)
1 1 mother cell divides intomother cell divides into 2 2 daughter daughter cells cells
Daughter cell is Daughter cell is identiidenticalcal to its mother to its mother Interphase + MitosInterphase + Mitosisis AllAll cells cells havehave 4646 chromosomes called chromosomes called
““DIPLODIPLOIID D cellscells”” Produce Produce SOMATISOMATIC cellsC cells ((not sexual cellsnot sexual cells))
Cellular ReproductionCellular Reproduction
22. . Sexual Reproduction (9 phases)Sexual Reproduction (9 phases)
11 mother cell divides intomother cell divides into 44 daughter daughter cellscells
Daughter cells have Daughter cells have ½ ½ the the chromosomes chromosomes of their mother of their mother (23) (23) ““HAPLOHAPLOIIDD cells cells ””
Interphase + MInterphase + Meeiosiosisis I + M I + Meeiosiosisis II II CCrossing overrossing over of genetic material often of genetic material often
occurs.occurs. SEXUSEXUAL cellsAL cells ( (eggegg and sperm) and sperm) known as known as
“ga“gammeetestes””
Asexual Asexual ReproductionReproduction
Sexual ReproductionSexual Reproduction
ProduProducesces __ __ daughter daughter cellscells
ProduProducesces __ __ daughter daughter cellscells
ProduProduces cells which ces cells which are _____ to their are _____ to their mother cellmother cell
ProduProduces cells which ces cells which are _____ to their are _____ to their mother cellmother cell
MMotherother:__chromosome:__chromosomessDaughterDaughter :__chromo :__chromo
MMotherother:__chromosome:__chromosomessDaughterDaughter :__chromo :__chromo
Asexual Asexual ReproductionReproduction
Sexual ReproductionSexual Reproduction
Crossing overCrossing over??
YESYES NO NOCrossing overCrossing over??
YESYES NO NO
______________ cells cells ______________ cells cells
DIPLODIPLOIID HAPLOD HAPLOIIDD DIPLODIPLOIID HAPLOD HAPLOIIDD
__ phases:__ phases: __ phases:__ phases:
GamGameetes…tes…don’t forget!! don’t forget!!
~ ~ Another name for Another name for eggseggs and and spermsperm
~ ~ They areThey are haplo haploiid (23 chromosomes)d (23 chromosomes)
~ ~ They are They are sexusexualal cell cellss
~ ~ They areThey are produ produced by sexual ced by sexual reproductionreproduction
TheThe ““nn” value” value
nn = = the basic (smallest) number of the basic (smallest) number of chromosomeschromosomes
Interphase Interphase ofof M Meeiosiosisis (4n = 92) (4n = 92)
AAfterfter T Teelophase I (2n = 46) lophase I (2n = 46)
Gametes Gametes at the end of at the end of MMeeiosiosisis ~ ~ afterafter
TTeelophase II ~ (n = 23)lophase II ~ (n = 23)
There are 3 major steps:There are 3 major steps:
~ Interphase~ Interphase
~ M~ Meeiosiosisis I I
~ ~ MMeiosiseiosis II II
SexuSexualal Reproduction Reproduction
HomologHomologousous ChromosomesChromosomes
A pair of A pair of chromosomeschromosomes ( (maternmaternal al andand paternpaternalal)) that have similar/identical that have similar/identical shapeshapes s andand sizes.sizes.
Have Have ggeenesnes for the same for the same cchharactaracteeristiristics cs (ie: (ie: eye coloreye color))..
EachEach locuslocus (g(geenene position) position) contrcontroolls the s the same traitsame trait and is inand is in the same place the same place on on homologous chromosomes. homologous chromosomes.
VocabulaVocabularyry
Homologous Chromosomes
chromatids chromatidstetrad
VocabulaVocabularyry
Sperm + egg = zygoteSperm + egg = zygote
HomologHomologous ous ChromosomesChromosomes
Paternal Maternal
Eye colorEye color
Hair color Hair color
Locus
Remember!! Remember!!
InterphaseInterphase
ProphaseProphase
MetaphaseMetaphase
AnaphaseAnaphase
TelophaseTelophase
Remember!! Remember!!
InterphaseInterphase
Prophase IProphase IMetaphase IMetaphase IAnaphase IAnaphase ITelophase ITelophase IProphase IIProphase II
Metaphase IIMetaphase IIAnaphase IIAnaphase IITelophase IITelophase II
MeiosisMeiosis
4n=92
2n=46
2n=46
meiosis I
n=23
n=23
n=23
n=23meiosis II
4 haploid
gamètes (n)
AfterInterphase
diploid (2n)
http://www.sumanasinc.com/http://www.sumanasinc.com/webcontent/animations/content/webcontent/animations/content/meiosis.htmlmeiosis.html
Interphase (4n = 92)Interphase (4n = 92) Same as Interphase in Same as Interphase in MitosMitosisis
Chromosome reChromosome replicationplication, growth and , growth and preparation (chromatin rolls etc)preparation (chromatin rolls etc)
Each of the Each of the rreepliplicated cated chromosomeschromosomes poss possessesesses 22 chromatideschromatides which are which are attachattacheded at at theirtheir centromcentromeerere..
Interphase (4n = 92)Interphase (4n = 92) We can see the nucleolus and the We can see the nucleolus and the
nuclear membrane. nuclear membrane.
Nuclear membrane
Nucleolus
Cell membrane
Chromatine
There are 92 chromosomes (46 pairs!!)
MMeeiosiosisis I ( I (44 phases) phases)
~ Prophase I~ Prophase I
~ M~ Meetaphase Itaphase I
~ Anaphase I~ Anaphase I
~ T~ Teelophase Ilophase I
Prophase I (4n = 92)Prophase I (4n = 92)
22 homolog homologousous chromosomes chromosomes combine. combine. This combination is called a This combination is called a TETRADTETRAD XXXX
Spindle fibers grow, and attach to each Spindle fibers grow, and attach to each side of the tetradside of the tetrad
TheThe nucnuclearlear memmembranebrane and theand the nuclnucleeololusus both disappear both disappear
Prophase I (4n = 92)Prophase I (4n = 92)
centriolesSpindle fibers
Crossing OverCrossing Over DurDuringing Prophase IProphase I
One chromatid of One chromatid of eacheach chromosome chromosome crosses over crosses over with with the chromatid of the the chromatid of the other chromosome. other chromosome.
TheThe r reesultsult is an is an exexchangechange of their of their genetic materialgenetic material
Crossing OverCrossing OverThe exchange of sections of homologous chromosomes in a TETRAD.
Maternalchromo
Paternalchromo
MMeetaphase I (4n = 92)taphase I (4n = 92)
Spindle fibers pull on the Spindle fibers pull on the tetrads, and align them in tetrads, and align them in the centre of the cell.the centre of the cell.
MMeetaphase I (4n = 92)taphase I (4n = 92)
Anaphase I (4n = 92)Anaphase I (4n = 92)
TheThe tetrads tetrads sseeparparate and ate and homologhomologououss chromosomes chromosomes travel to the polestravel to the poles. .
HHomologues chromosomes omologues chromosomes are still attached by their are still attached by their centromcentromeeresres..
Anaphase I (4n = 92)Anaphase I (4n = 92)
TTeelophase I/lophase I/CytokenisisCytokenisis (2n = 46)(2n = 46)
EachEach p poole le has a has a diplodiploiidd number of number of cchromosomes.hromosomes.
Cytokenisis Cytokenisis - - 22 diplo diploiids cells ds cells areare form formeded. .
Spindle fibers Spindle fibers and and centriolescentrioles disappear.disappear.
The nuclear membrane sometimes The nuclear membrane sometimes reforms, and the nucleolus does not reforms, and the nucleolus does not reform at this point. reform at this point.
Telophase I (2n = 46)Telophase I (2n = 46)
Cell divisionCell division
MMeeiosiosisis II ( II (44 phases) phases)~ Prophase II~ Prophase II
~ Metaphase II~ Metaphase II
~ Anaphase II~ Anaphase II
~ T~ Teelophase IIlophase II
MMeeiosiosisis II II
Interphase II Interphase II – – does not existdoes not exist
** ** Don’t forgetDon’t forget!! !! This process is This process is occuring in both daughter cells occuring in both daughter cells created during Meiosis I created during Meiosis I ****
Prophase II (2n = 46)Prophase II (2n = 46)
Same as Same as ProphaseProphase inin MitosMitosisis
MMeetaphase II (n = 46)taphase II (n = 46)
Same as Same as MMeetaphasetaphase inin MitosMitosisis
Anaphase II (2n = 46)Anaphase II (2n = 46)
Same as Same as AnaphaseAnaphase inin MitosMitosisis DON’T FORGETDON’T FORGET! ! CChromosomes hromosomes are are
separated into chromatids.separated into chromatids.
Télophase II/Télophase II/CytokenisisCytokenisis (n = (n = 23)23)
Same as Same as TelophaseTelophase inin MitosMitosisisEXCEPT n = 23
The nucleolus and nuclear membrane The nucleolus and nuclear membrane reformreform
CytokenisisCytokenisis
Important: Important: 4 haplo4 haploiid gamd gameetes tes areare form formeded..
Telophase II/Telophase II/Cytokenisis Cytokenisis (n = (n = 23)23)
Meiosis– http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter28/animation__how_meiosis_works.html
Attention!!!!!!!!!!!!!Attention!!!!!!!!!!!!!
Female meiosis is somewhat Female meiosis is somewhat different. 4 gametes are different. 4 gametes are initially created, but initially created, but Cytokenisis is UNEQUAL.Cytokenisis is UNEQUAL. In In this case, this case, ONE GAMETE ONE GAMETE survives, and the other 3 are survives, and the other 3 are not viable.not viable.
MitosMitosisis vs M vs Meeiosiosisis
MitosMitosisis MMeieiososisis
ResultResult 2 diplo2 diploiid cells d cells (2n)(2n)
44 hahaploploiid cellsd cells (n)(n)
The cells areThe cells are iidentidenticalcal diffdiffeerentrent
Occurs inOccurs in somatisomaticc ccellules (all ellules (all cells in the cells in the body)body)
sexusexualal
CCellules ellules (sperm and (sperm and egg)egg)
Meiosis– United Streaming
Visual RepresentationsVisual Representations
http://www.cellsalive.com/meiosis.htmhttp://www.cellsalive.com/meiosis.htm
http://www.csuchico.edu/~jbell/Biol207/http://www.csuchico.edu/~jbell/Biol207/animations/meiosis.htmlanimations/meiosis.html
http://www.sumanasinc.com/http://www.sumanasinc.com/webcontent/animations/content/webcontent/animations/content/meiosis.htmlmeiosis.html