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Biology Ch. 11
| Term | Definition |
|---|---|
| Genetics | scientific study of heredity |
| Fertilization | process in sexual reproduction in which male and female reproductive cells join to form a new cell. |
| Trait | specific characteristic of an individual |
| Hybrid | offspring of crosses between parents with different traits |
| Gene | sequence of DNA that codes for a protein and thus determines a trait; factor that is passed from parent to offspring. |
| Allele | one of a number of different forms of a gene. |
| Principle of Dominance | Mendel's second conclusion, which states that some alleles are dominant and others are recessive. |
| Segregation | separation of alleles during gamete formation |
| Gamete | sex cell |
| Probability | likelihood that a particular event will occur |
| Homozygous | having two identical alleles for a particular gene |
| Heterozygous | having two different alleles for a particular gene |
| Phenotype | physical characteristics of an organism |
| Genotype | genetic makeup of an organism |
| Punnett square | diagram that can be used to predict the genotype and phenotype combinations of a genetic cross. |
| Independent assortment | one of Mendel's principles that states that genes for different traits can segregate independently during the formation of gametes. |
| Incomplete dominance | situation in which one allele is not completely dominant over another allele |
| Codominance | situation in which the phenotypes produced both by both alleles are completely expressed. |
| Multiple allele | a gene that has more than two alleles |
| Polygenic trait | trait controlled by two or more genes |
| Homologous | term used to refer to chromosomes in which one set comes from the male parent and one set comes from the female parent. |
| Diploid | term used to refer to a cell that contains two sets of homologous chromosomes |
| Haploid | term used to refer to a cell that contains only a single set of chromosomes. |
| Meiosis | process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell |
| Tetrad | structure containing four chromatids that forms during meiosis |
| Crossing-over | process in which homologous chromosomes exchange portions of their chromatids during meiosis. |
| Zygote | fertilized egg |