Transcript Science 7
Today’s Agenda… Bellringer: Life Science Multiple Choice Questions Discuss homework from last night Notes on Human Genetic Disorders Human Genetic Disorders Study Pack #13 Genetic Disorders An abnormal condition that a person inherits through genes or chromosomes Caused by mutations or changes in a person’s DNA Mutations may occur during meiosis Mutations may be passed on from a parent Cystic Fibrosis Produces abnormally thick mucus in the lungs and intestines Difficult to breath Difficult for digestion to occur Carried on a recessive allele No cure, only treatments Medicines and physical therapy Sickle-Cell Disease Red blood cells have an unusual “sickle” shape Cannot carry as much oxygen as normal blood cells Get stuck in blood vessels Suffer from lack of oxygen in blood Experience pain and weakness The allele is codominant with the normal allele If the person is a hybrid, they will produce both normal and sickle cells Malaria Hemophilia A person’s blood clots very slow or not at all Person can bleed to death from a minor cut Caused by recessive allele on X chromosome Sex-linked disorder Occurs more in males Down Syndrome A person’s cells have an extra copy of chromosome 21 Error during meiosis Chromosomes fail to separate properly when sex cells are formed Distinct physical appearance Mental retardation Diagnosing Genetic Disorders Amniocentesis Doctor removes fluid surround baby and examines the chromosomes from the cells Can determine whether the baby has the correct number of chromosomes and whether it’s a boy or girl Genetic Counseling Help couples understand the chances of having a baby with a genetic disorder Use Punnett squares, pedigrees, karyotypes Karyotype A picture of a person’s chromosomes Pedigrees Page 319 A visual tool for following a trait through generations of a family Males are squares, females are circles Colored circles show where the trait is expressed Pedigrees Half colored circles are carriers Heterozygous for the trait but it is not seen in the individual Can pass the trait on to offspring Homework… Choose 2 of the genetic disorders we have discussed today and in your OWN words, describe how each is inherited.