PSYCH 130 Chapter Notes - Chapter 3.1: Twin, Fertility Medication, Allosome
25 Nov 2017
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Mitosis: duplication of dna through cell division. Chromosomes copy themselves so each new cell contains the same number of chromosomes and identical genetic info. Proteins coded by genes are responsible for differences as well as communication system between the cell nucleus and cytoplasm. Formed through meiosis which halves the # of chromosomes normally present in body cells. Zygote: cell that results when sperm and ovum unite during fertilization. Has 46 chromosomes; 23 from the mother and 23 from the father. Crossing over: chromosomes next to each other break at one or more points along their length and exchange segments so that genes from one are replaced by genes from another. Creates new hereditary combinations which increases the chances that at least some members of a species will cope with changing environments and survive. Makes it highly unlikely that non-twin siblings will be genetically identical. 4 sperm results from meiosis while only one ovum is formed.
