Biology notes for genetics.

Genetics still rely on Mendel's model to predict the likely outcome of genetic crosses. Capital letters refer to dominant alleles, and lowercase letters refer to recessive alleles. Capital and lowercase forms of the same letter must be used to designate the two forms of one gene. The allele for a dominant trait of tallness in pea plants is represented by T, and the allele for the recessive trait of shortness by t. Since there are …

…blood circulationAbnormal hemoglobin moleculesRecessive Tay-Sachs diseaseDeterioration of central nervous system in infancy; usually don't survive to adulthoodDefective form of enzyme hexosaminidase ARecessive PhenylketonuriaFailure of brain to develop in infancy; usually don't survive to adulthood (if untreated).Defective form of enzyme phenylalanine hydroxylaseRecessive Huntington's DiseaseGradual deterioration of brain tissue in middle age; shortened life expectancyProduction of an inhibitor of brain cell metabolism.Dominant Muscular DystrophyWasting away of muscles; shortened life expectancyMuscle fibers degenerate and atrophySex-linked Recessive