Kinesiology 3347A/B Lecture Notes - Lecture 5: Artificial Insemination, Cryopreservation, Egg Cell
27 Jan 2020
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Document Summary
The first step in development of an individual human being happens at conception, when each of us receives a combination of genes that will shape our experiences throughout the rest of our lives. Occurs when a sperm penetrates an ovum. Most cells in the human body contain 23 pairs of chromosomes. Gametes cells that only have 23 chromosomes. At conception 23 chromosomes of the sperm unite with chromosomes of the ovum. Fertilized egg has 23 pairs of chromosomes in an entirely new cell called a zygote: more or less negative health consequences, down syndrome, turner"s syndrome, etc. Women contain only x chromosomes, their ova carry x. Half of men"s sperm contains x, the other half contains y. Consequently, the sex of the new individual is determined by the sex of the chromosome in the sperm: xx female, xy male. Most humans are conceived and born one at time. 3% of births are multiples, usually twins (90%)
