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.