| gene | carrier of hereditary information |
| allele | half a gene, carrier of a hereditary trait |
| homozygote | an individual with genes composed of identical alleles (RR or rr) |
| heterozygote | an individual with genes composed of different alleles (Rr) |
| chromosome | collection of a species' genes in its cells |
| chromatid | a full replica of a chromosome before mitosis; the chromosome then consists of two linked chromatids |
| gamete | sex cell, carries half of a species' genetic information (alleles) |
| meiosis | formation of two gametes through cell division; each gamete receives half a chromosome |
| mitosis | formation of two new cells through cell division; each cell receives a full chromosome |