Psychology 2040A/B Chapter Notes - Chapter 3: Xyy Syndrome, Trisomy, Egg Cell
5 Feb 2014
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Conception: zygote- 46 chromosomes, 23 from each parent. Each chromosome contains genes, made up of dna. Monozygotic (identical): a zygote that divides to form two genetically identical individuals (1 in 250 births) Dizgotic (fraternal): occurs when two ova are released simultaneously and both are fertilized by different sperm (1 in 125 births) Therefore sex of child is determined by father"s sperm. Direct production of amino acids necessary for forming new cells. Guide cells to develop different parts of body. May turn on or turn off other genes. If two alleles are homozygous: they are both dominant or recessive. If two alleles are heterozygous: one is dominant and one is recessive. If two alleles are codominant: they are each heterozygous and equal. Dominant (dark hair, curly hair, pigmented skin, type a blood, facial dimples, farsightedness) Recessive (blond hair, straight hair, albinism, type o blood, no dimples, normal vision) During cell division in meiosis, distribution of chromosomes may be uneven.
