2 - Heredity and Conception

2 - Heredity and Conception - Chapter 2: Heredity and...

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Chapter 2: Heredity and Conception Biological and Genetic Foundations Heredity and environment are the foundations of development Heredity: The biological transmission of traits and characteristics from one generation to another. Chromosomes: Store/transmit genetic information. Gene: A segment of a DNA molecule. There are two types of cell division: o Mitosis: Cell-division process by which growth occurs and tissues are replaced. o Meiosis: Sperm and ova are produced by reduction division, and have 23 rather than 46 chromosomes. Determining gender: Boy or Girl? o Sex chromosomes o We all receive an X chromosome from our mothers, and we receive either an X or Y from our fathers o Females have XX o Males have XY Multiple Births o Fraternal (dizygotic): Two eggs, two sperm o Identical (monozygotic): One egg, one sperm Patterns of Genetic Inheritance Traits are determined by pairs of genes Each member of a pair of genes is an allele Mutation: A permanent change in a DNA segment, happens by chance or a result of hazardous substance in the environment. Chromosomal abnormalities: Most appear during the process of meiosis. Genetic Counseling and Prenatal Testing Genetic counseling may be sought by couples who have had problems conceiving, repeated miscarriages, or know that genetic problems exist in their families. Prenatal testing can indicate whether the fetus is carrying genetic abnormalities.
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2 - Heredity and Conception - Chapter 2: Heredity and...

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