Welcome Back! Take one of each copy from the front table next to the door. Copy the following vocabulary terms on the blank page of the fill-in notes… • Gene-section of a chromosome that codes for a trait • Allele-distinctive form of a gene • Recessive allele-form of a gene that is not expressed when paired with a dominant allele • Dominant allele-form of a gene that is fully expressed when 2 different alleles are present • Punnett square-A chart used to solve genetic problems • Monohybrid cross-A cross consisting of only one type of trait • Dihybrid cross-A cross consisting of two types of characteristics • Trait-Characteristic • Phenotype-The outward appearance of a characteristic (brown hair, blue eyes) • Genotype-The genetic make-up of an organism (Tt, Rr, Aa) • Homozygous- The alleles in a pair are identical (TT, rr) • Heterozygous-The alleles in a pair are different (Tt, Aa) • Test cross-The mating of a homozygous recessive individual with an unknown genotype for a characteristic • Hybrid-Organism that receives different forms of a genetic trait from each parent • Purebred-Organism that receives the same genetic trait from both parents