| A | B |
|---|
| heredity | the passing of traits from parents to offspring |
| trait | a characteristic that an organism can pass on to its offspring through its genes |
| genetics | the scientific study of heredity |
| fertilization | the joining of a sperm and an egg |
| purebred | the offspring of many generations that have the same traits |
| gene | the set of information that controls a trait; a segment of DNA on a chromosone that codes for a specific trait |
| alleles | the different forms of a gene |
| dominant allele | an allele whose trait always shows up in the orgnism when the allele is present |
| recessive allele | an allele that is masked when a dominant allele is present |
| hybrid | an organism that has two different alleles for a trait; an organism that is heterozygous for a particular trait |
| probability | the number that describes how likely it is that an event will occur |
| Punnett square | a chart that shows all the possible combinations of alleles that can result from a genetic cross |
| phenotype | an organism's physical appearance, or visible traits |
| genotype | an organisms genetic makeup, or allele combinations |
| homozygous | having two identical alleles for a trait |
| heterozygous | having two different alleles for a trait |
| meiosis | the process that occurs in the formation of sex cells (sperm and egg) by which the number of chromosomes is reduced by half |
| mutation | a change in a gene or chromosome |
