| 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 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 chromosome that codes for a specific trait |
| alleles | different forms of a gene; ex. tall or short |
| dominant allele | allele whose trait always shows up in the organism when the allele is present; use a capital letter to represent |
| recessive allele | allele that is masked (or hidden) when a dominant allele is present; use a lower case letter to represent |
| hybrid | organism that has two different alleles for a trait: an organism that is heterozygous for a particular trait |
| probability | a 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 appearence or visible traits; such as pink |
| genotype | organism's genetic makeup or allele combinations; such as Pp |
| homozygous | having two identical alleles for a trait; such as AA or aa |
| heterozygous | having two different alleles for a trait; such as Cc |
| codominance | condition in which neither of two alleles of a gene is dominant or recessive; both will show up; example AB blood type |
| messenger RNA | RNA that copies the coded message from 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 | change in a gene or chromosome |
| meiosis | process that occurs in the formation of sex cells by which the number of chromosomes is reduced by half |
