PSY106Chap2b

PSY106Chap2b - Chapter Review After reading this chapter,...

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Chapter Review After reading this chapter, students should understand that: The human genetic code transmitted at conception from the mother and father and embedded in the first, single cell, determines the process that transforms the single cell into a person. Genes are composed of specific sequences of DNA molecules which are arranged in specific locations and in a specific order along 46 chromosomes (23 pairs). A child’s mother and father each provide one of the two chromosomes in each of the 23 chromosomal pairs. At conception, the 23 maternal and 23 paternal chromosomes unite within a single cell, called the zygote, which contains the genetic blueprint that will guide cell activity for the rest of the individual’s life. The potential for the vast diversity of human beings is a result of the process of cell division of the gametes and random transformations of particular genes. Some multiple births occur when a cluster of cells in the ovum splits off within the first two weeks after fertilization, resulting, at birth, in monozygotic twins. Some multiple births occur when two separate ova are fertilized by two separate sperm at roughly the same time, resulting at birth, in dizygotic twins. The odds for having multiple births increases with the use of fertility drugs and is influenced by racial, ethnic, and national differences. The sex of a child is determined by the 23rd chromosomal pair; in females, the 23rd pair consists of two matching X-shaped chromosomes and in the male, the 23rd pair consists of an X-shaped chromosome and a smaller Y-shaped chromosome; the father’s sperm determines the sex of the child. When two competing traits are present, the one that gets expressed is the dominant gene and the one that is not expressed is the recessive gene. The genotype is the underlying combination of genetic material present in an organism and the
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PSY106Chap2b - Chapter Review After reading this chapter,...

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