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Unit 4 –Reproduction and Genetics Lesson 11 - Gamete Production PowerPoint Presentation
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Unit 4 –Reproduction and Genetics Lesson 11 - Gamete Production

Unit 4 –Reproduction and Genetics Lesson 11 - Gamete Production

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Unit 4 –Reproduction and Genetics Lesson 11 - Gamete Production

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  1. Unit 4 –Reproduction and Genetics Lesson 11 - Gamete Production Colorado Agriscience Curriculum

  2. Unit 4, Lesson 11 - Gamete Production

  3. I: Production of Gametes • A) Gametogenesis • 1. Ovaries produce ova • a) Oogenesis • 2. Testicles produce sperm • a) Spermatogenesis • 3. Sex cells divide by meiosis • a) Special cell division in which each new gamete(cell) carries only 1/2 the # of chromosomes a typical cell would in that species Unit 4, Lesson 11 - Gamete Production

  4. I: Production of Gametes • B) Initial steps are similar between male and female • 1. Chromosomes replicate • a) Each is doubled • 2. Each pair comes together very accurately (synapsis) • a) Now called a primary oocyte or • b) Primary spermatocyte Unit 4, Lesson 11 - Gamete Production

  5. II. Spermatogenesis • A. Primary Spermatocyte • 1. Contains 2 pair of chromosomes • a) Two bodies containing 4 structures • 2 rapid cell divisions produce 4 cells • a) Each ontain 2 chromosomes • b) Spermatid cells lose much of their cytoplasm & develop a tail Unit 4, Lesson 11 - Gamete Production

  6. Unit 4, Lesson 11 - Gamete Production

  7. III: OOGENESIS • A. 1st maturation division • 1. Produce 1 large oocyte (secondary) & 1 small (1st Polar Body) • a) Unequal size results from body wanting one rich in nutrients @ the expense of the other • B. 2nd maturation division • 1. Produces the ovum • a) Polar bodies may divide but will soon die and be reabsorbed by the body Unit 4, Lesson 11 - Gamete Production

  8. Unit 4, Lesson 11 - Gamete Production

  9. IV: Fertilization • A) Fertilization is the union of sperm and ovum and the establishment of paired chromosomes • 1. Zygote is a diploid (Double) because chromosomes are in pairs • a) 1 member of each pair came from the sire and 1 from the dam Unit 4, Lesson 11 - Gamete Production

  10. IV: Fertilization • B) Gametes have only one member of each pair. • 1. Haploid (Half) • 2. Gametogenesis reduces the # of chromosomes in a cell to 1/2 the diploid # • 3. Each gamete carries a random sampling 1/2 of each parents genetic code. • 4. Which sperm fertilizes the ovum is also random • a) This insures genetic diversity Unit 4, Lesson 11 - Gamete Production

  11. Unit 4, Lesson 11 - Gamete Production