2 gametogenesis
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Transcript of 2 gametogenesis
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(1)GAMETOGENESIS(1)GAMETOGENESIS In preparation for fertilization both male & female germ cells In preparation for fertilization both male & female germ cells
undergo a chromosomal & morphological changes which is undergo a chromosomal & morphological changes which is known as Gametogenesisknown as Gametogenesis
TypesTypes Spermatogenesis - Development of mature spermatozoa or Spermatogenesis - Development of mature spermatozoa or
spermsperm Oogenesis – Development of mature ovaOogenesis – Development of mature ova
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(2)Mieosis(2)Mieosis
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SpermatogeneSpermatogenesissis
46, 2N
46 , 4N
23, 2N
23, 1N
23, 1N
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OogenesisOogenesis46, 2N
46 , 4N
23, 2N
23, 1N
23, 1N
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SPERMATOGENESISSPERMATOGENESIS
Time of beginning – Shortly before pubertyTime of beginning – Shortly before puberty Site – Seminiferous tubuleSite – Seminiferous tubule COMPLETES TWO MEIOTIC DIVISIONSCOMPLETES TWO MEIOTIC DIVISIONS CREATES FOUR EQUAL HAPLOID SPERMSCREATES FOUR EQUAL HAPLOID SPERMS
OOGENESISOOGENESIS
Time of beginning – Intra uterine lifeTime of beginning – Intra uterine life Site – Ovarian cortexSite – Ovarian cortex STOPS AT PROPHASE OF THE MEIOTIC DIVISION UNTIL OVULATION.STOPS AT PROPHASE OF THE MEIOTIC DIVISION UNTIL OVULATION. AT THE TIME OF OVULATION,THE OOCYTE GOES TO METAPHASE OF SECOND AT THE TIME OF OVULATION,THE OOCYTE GOES TO METAPHASE OF SECOND
MEIOSIS.MEIOSIS. CREATES 1 OOCYTE AND 3 POLAR BODIESCREATES 1 OOCYTE AND 3 POLAR BODIES
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Sperm AnatomySperm AnatomyStreamlined to swim through vagina, cervix, Streamlined to swim through vagina, cervix,
uterus ductuterus duct AcrosomeAcrosome – part of head, contains – part of head, contains
enzymes to penetrate eggenzymes to penetrate egg Haploid nucleusHaploid nucleus Mitochondria to supply energy (sugar in Mitochondria to supply energy (sugar in
semen)semen) Flagellum to propel spermFlagellum to propel sperm
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