2 gametogenesis

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2 gametogenesis

  1. 1. (1)GAMETOGENESIS  In preparation for fertilization both male & female germ cells undergo a chromosomal & morphological changes which is known as Gametogenesis Types  Spermatogenesis - Development of mature spermatozoa or sperm  Oogenesis – Development of mature ova 1
  2. 2. (2)Mieosis 2
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  4. 4. Spermatogenesi s 46, 2N 46 , 4N 23, 2N 23, 1N 23, 1N 4
  5. 5. Oogenesis 46, 2N 46 , 4N 23, 2N 23, 1N 23, 1N 5
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  7. 7. SPERMATOGENESIS  Time of beginning – Shortly before puberty  Site – Seminiferous tubule COMPLETES TWO MEIOTIC DIVISIONS  CREATES FOUR EQUAL HAPLOID SPERMS OOGENESIS    Time of beginning – Intra uterine life Site – Ovarian cortex STOPS AT PROPHASE OF THE MEIOTIC DIVISION UNTIL OVULATION.  AT THE TIME OF OVULATION,THE OOCYTE GOES TO METAPHASE OF SECOND MEIOSIS.  CREATES 1 OOCYTE AND 3 POLAR BODIES  7
  8. 8. Sperm Anatomy Streamlined to swim through vagina, cervix, uterus duct  Acrosome – part of head, contains enzymes to penetrate egg  Haploid nucleus  Mitochondria to supply energy (sugar in semen)  Flagellum to propel sperm 8
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