| Terms | Definitions |
| Heredity | the biological inheritance of an organism |
| Genetics | study of heredity |
| Trait | Characteristic that distinguishes one individual from another |
| Hybrid | description of offspring of parents with different characteristics |
| Gene | DNA segment that controls traits |
| Alleles | different forms of a gene ex. brown, red and blond hair. |
| Dominant | form of an allele that is expressed even when present with a contrasting allele, Capital letters |
| Recessive | form of an allele that is expressed only when a contrasting alleles not present, lower case letters |
| Phenotype | Form of a trait that an organism displays |
| Genotype | genetic composition of an organism BB,Bb,bb |
| Who is Gregor Mendel | monk who lived in the mid 1800's who discovered that traits were passed on by physical units he called Merkmals(genes); the father of genetics. |
| Mendel's 1st Principle | individual units, called genes, determine biological characteristics |
| Mendel's 2nd Principle | For each gene, an organism receives one allele from each parent. The alleles separate from each other -a process called segregation - when reproductive cells are formed |
| Mendel's 3rd Priciple | If an Organism inherits different alleles for the same trait, one allele may be dominate over the other |
| Mendel's 4th Principle | Some genes segregate independently |
| Homozygous | description of an organism that has an identical pair of alleles for a trait |
| Heterozygous | description of an organism that has two different alleles for a trait |
| segregation | process that separates the two allels of a gene |
| Independent Assortment | process by which genes segerate independently |
| True Breeding | stock that always passes its characteristics to the next generation |
| Cross Pollinating | cross two different types of true breeding plants |
| Self Pollinating | when a plant has both its male and female parts so there is no chance of cross polination |
| linked genes | genes on the same chromosome |
| crossing-over | exchange of genetic material between homologous chromosomes that produces more possible combinations of genetic material than would exist otherwise |
| Punnett square | are used to predict the genetic variations that will result in the phenotypes and genotypes of offspring |
| Upper Case letters | Represent dominant alleles(genes for a trait) |
| Lower case Letters | represent recessive alleles |
| P Generation | Parent Generation (usually homozygous for traits) |
| F1 Generation | the hybrid offspring of the P generation. |
| pure bred | an individual that is dominant for a trait. They have no other alleles. |
| probability | the likelihood that a particular event will occur |
| Two Factor cross | a punnet square that showed that in pea plants traits are independently assorted |
| incomplete dominance | when one allele is not completely dominent over the another and the result is a trait that is between the two phenotypes |
| co-dominance | when both alleles contribute to the phenotype, ex. a black and white cow. Not a gray cow. |
| multiple alleles | when a single gene has more than two alleles. They could have a red, white or blue phenotype. |
| polygenic | the most complex traits because the phenotype is caused by more than two alleles. This means that there is a large variation in the way an individual looks |
