| 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 |
| purebred | An organism that always produces offspring with the same form of a trait as a parent |
| gene | A segment of DNA on a chromosome that codes for a specific trait |
| alleles | The different forms of a gene |
| 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 likelihood that a particular event will occur |
| Punnet square | A chart that shows all the possible combinations of alleles that can result from a genetic cross |
| phenotype | An organism's physical apperance, or visible traits |
| genotype | An organism's genetic makeup, or allele combination |
| homozygous | Having two identical alleles for a trait |
| heterozygous | Having two different alleles for a trait |
| codominance | A condition in which neither of the two alleles of a gene is dominant or recessive |
| sperm | A male sex cell |
| egg | A female sex cell |
| meiosis | The process that occurs in sex cells (sperm and egg) by which the number of chromosomes is reduced by half |
| messenger RNA | RNA that copies the coded message from the DNA in the nucleus and carries the message into the cytoplasm |
| transfer RNA | RNA in the cytoplasm that carries an amino acid to the ribosome and adds it to the growing protein chain |
| mutation | A type of symbiosis in which both partners benefit from living together |
