Chapter+9+vocabbb

Genetics Vocabulary Genetics - the field of biology dedicated to understanding how characteristics are transmitted from parents to offspring Heredity - the transmission of characteristics form parent to offspring Self Pollination-when pollen is transferred from the anthers of a flower to the stigma of either the same flower or a flower on the same plant Allele - an alternative form of a gene Cross-pollination - a reproductive process in which pollen from one plant is transferred to the stigma of another plant Dominant - refering to an alele that masks the presence of another allele for the same characteristic Genes - a unit of hereditary information Hybrid - the offspring of two different animal species Recessive - referring to an allele that is masked by the presence of another allele for the same characteristic Phenotype - the external appearance of an organism that is determined by the individual's genotype Genotype - the genetic makeup of an organism Heterozygous - when two alleles in a pair are different Homozygous - when both alleles of a pair are alike

Mutations and Disorders Huntington's Disease (HD) - a human genetic disorder caused by a dominant allele resulting in involuntary movements, mental deterioration, and eventual death Nondisjunction - the failure of a chromosome to separate from its homologue in meiosis Deletion - the loss of a piece of a chromosome due to chromosomal breakage Translocation - a mutation where a chromosome piece breaks off and attaches to another nonhomologous chromosome Inversion - when a chromosomal segment breaks off, then reattaches in reverse orientation to the same chromosome Sickle-Cell Disease - a genetic disorder caused by the autosomal recessive allele that results in impaired blood circulation and organ damage Phenylketonuria (PKU) - a genetic disorder caused by the autosomal recessive allele that results in failure of the brain to develop in infancy, and if this is left untreated, eventual death in childhood Cystic Fibrosis - genetic disorder caused by the autosomal recessive allele that results in mucus cloging lungs, liver, and pancreas. Victims don't usually survive to adulthood. Hemophilia - an X-linked recessive trait that impairs the ability of blood to clot following a cut, bruise or other injury. Duchenne Muscular Dystrophy - another X-linked recessive trait that weakens and progressively destroys muscle tissue Down Syndrome - a triosomy resulting in an extra 21 chromosome, which includes mild to severe mental retardation, characteristic facial features, muscle weakness, heart deffects and short stature