| A | B |
|---|
| genetics | the study of how traits are inherited |
| genotype | uses symbols to express the kind of alleles an individual carries |
| phenotype | physical expression of a trait |
| heterozygous | carries two different alleles for a trait |
| homozygous | both alleles for a trait are the same |
| purebred | like homozygous, both alleles are the same |
| hybrid | like heterozygous |
| Punnett Square | chart showing possible combinations of genes in offspring |
| homologous chromosome | chromosome that occurs in a pair |
| gametes | reproductive cells (haploid) |
| zygote | fertilized egg cell (diploid) |
| gene | portion of DNA coding for a trait |
| mitosis | cell division resulting in 2 diploid cells |
| meiosis | cell division resulting in haploid cells |
| crossing over | process when homologous chromosomes exchange portions of their chromatids during meiosis |
| allele | one of a number of different forms of the same gene |
| dominant | gene that is expressed even when recessive allele is present |
| recessive | allele expressed only when homozygous |
| heredity | the study of how traits are passed from one generation to the next |
| segregation | separation of alleles during gamete formation |
| independent assortment | genes on different chromosomes segregate independently during meiosis |
| test cross | cross between an organism of unknown genotype and a homozygous recessive |
| Gregor Mendel | used pea plants to establish the basic principles of genetics |
