Post on 06-Jan-2018
description
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.