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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44

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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