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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 |