meiosis object: to study the meiosis through its subsequent developmental stages and discuss its...
DESCRIPTION
Meiosis Meiosis in males is called spermatogenesis and produces sperms. Meiosis in females is called oogenesis and produces ova. Two divisions (meiosis I and meiosis II).TRANSCRIPT
MEIOSISMEIOSIS
Object: to study the meiosis through Object: to study the meiosis through its subsequent developmental stages its subsequent developmental stages and discuss its Genetics Significant..and discuss its Genetics Significant..
• Meiosis in Meiosis in malesmales is called is called spermatogenesisspermatogenesis and produces and produces spermssperms..
• Meiosis in Meiosis in femalesfemales is called is called oogenesisoogenesis and and produces produces ovaova..
•Two divisionsTwo divisions ( (meiosis I meiosis I and and meiosis IImeiosis II).).
MeiosisMeiosis
2n
n
n
1 cell division: 1 cell division: 2 daughter cells2 daughter cells
2 cell divisions: 2 cell divisions: 4 cells product 4 cells product of meiosisof meiosis
2n
2n
2nn
n n
n
n=chromosome numbern=chromosome number
Somatic cellsSomatic cells
Cells in sexual cycleCells in sexual cycle
MITOSISMITOSIS
MEIOSISMEIOSIS
definitionsdefinitions
• Homologous Homologous chromosomes:chromosomes: the members of a the members of a chromosome pair chromosome pair that is identical that is identical in the in the arrangement of arrangement of genesgenes
Homologous ChromosomesHomologous Chromosomes
PaternalPaternal MaternalMaternal
eye coloreye color locuslocus
eye coloreye color locuslocus
hair colorhair color locuslocus
hair colorhair color locuslocus
• Synapsis: (Synapsis: (التشابكالتشابك)) the intimate association the intimate association
وثيق وثيق ترابط of ) of (((ترابطhomologous homologous chromosomes…chromosomes…
Homologous chromosomes
definitionsdefinitions
definitionsdefinitions
• Crossing-over: Crossing-over: ((العبورالعبور))
a term describing the a term describing the process of process of reciprocal reciprocal chromosomalchromosomal interchange by which interchange by which recombinants ariserecombinants arise
Crossing overPairing of
homologous chromosomesChiasmaChiasma formationChromosomes
Breakage and joining
Recombinant chromosomes
MEIOSIS I
• Prophase I
• The The longestlongest phase. phase. This phase can be This phase can be divided into 5 stages;divided into 5 stages;
a)a) LeptoteneLeptoteneb)b) ZygoteneZygotenec)c) PachytenePachytened)d) DiploteneDiplotenee)e) DiakinesisDiakinesis
1 .Leptotene
2.Zygotene
3.Pachytene 4.Diplotene 5.Diakinesis
Prophase I
Metaphase I Anaphase I
Telophase IProphase II
Prophase I
Meiosis 2Meiosis 2ndnd division: division: like mitosislike mitosis with haploid set with haploid set
4 Haploid cells Gametes4 Haploid cells Gametes
Mitosis vs MeiosisMitosis vs Meiosis
MitosisMitosis MeiosisMeiosisResults inResults in 2 Diploid Cells 2 Diploid Cells
(2N)(2N)4 Haploid Cells 4 Haploid Cells (N)(N)
Cells areCells are Genetically Genetically IdenticalIdentical
Genetically Genetically DifferentDifferent
Occurs inOccurs in Somatic (Body) Somatic (Body) CellsCells
Sex CellsSex Cells
Prophase IProphase I
Slides for Meiosis I & II:Slides for Meiosis I & II:
Metaphase I:Metaphase I:
Anaphase I:Anaphase I:
Telophase I:Telophase I:
Prophase II:Prophase II:
Metaphase II:Metaphase II:
Anaphase II:Anaphase II:
Telophase II:Telophase II:
Final result
Meiosis :Four genetically different haploid cells from one diploid parent cell
Mitosis :two genetically identical diploid cells from one diploid parent cell