Meiosis Gametogenesis

Meiosis in Male and Female In males is called spermatogenesis and produces sperm. In females is called oogenesis and produces ova.

Spermatogenesis

Spermatogenesis The male gamete is called a spermatozoa Four spermatocytes are formed during meiosis Men are busy - meiosis produces roughly 250,000 sperm a day.

Oogenesis The female gamete is called an ovum At birth each female carries a lifetime supply of developing oocytes, each of which is in Prophase I. A developing egg (secondary oocyte) is released each month from puberty until menopause, a total of 400-500 eggs.

Oogenesis Only one ovum is produced during meiosis Oogenesis places most of the cytoplasm into the large egg. The other cells, the polar bodies, do not develop.

Human Fertilization ZYGOTE – fertilized egg Gametes

In Humans Example: 23 chromosomes in haploid n = 23 2n = 223 = ~ 6 million possible combinations!

Random fertilization At least 6 million combinations from Mum and another 6 million from Dad … >36 trillion combinations for a diploid zygote!!!

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