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Chapter 3
cells and heredity
Term | Definition |
---|---|
Heredity | the passing of traits from parents to off spring |
Trait | a specific characteristic that an organism can pass to its offspring through genes |
Genetics | the scientific study of heredity |
Fertilization | the process in sexual reproduction which an egg cell and sperm cell join to form a new cell |
Purebread | an offspring of many generations that has the same form of traits |
Gene | a sequence of DNA that determines a trait and is passed from parent to offspring |
Allele | The different forms of a gene |
Dominate Allele | An allele whose traits always shows up in the organism when the allele is present |
Recessive Allele | an allele that is hidden whenever the dominate allele is present |
Hybrid | An offspring of crosses that has two different alleles for a trait |
Probability | A number that describes the likely hood it is that a particular event will ocour |
Punnett Square | A chart that shows all the possible combinations of alleles that can result from a genetic cross |
Phenotype | AN organisms physical appearance or visible trait |
Genotype | an organisms genetic makeup, or allele combitnations |
Homozygous | having two identical alleles for a particular gene |
Heterzygous | having two different alleles for a particular gene |
incomplete dominance | a situation in which one allele is not completely dominate over another allele |
codominance | a situation in which both alleles for a gene are expressed equally |
multiple alleles | three or more possible alleles of a gene that determines trait |
polygenic inheritance | the inheritance of traits that are controlled by two or more gene, such as height in humans |
meiosis | the process that occurs in the formation of sex cells (sperm and egg)which the number chromosomes is reduced by half |