5.2 Human Genetic Disorders

1
5.2 Human Genetic Disorders

• Why do some people have disorders like Down
  Syndrome? How do are genes determine this?

2
Intro-Personal Connection

• Does anyone know a friend or family member with a
  genetic disorder?

3
Lab Zone

• Discovery Activity page 151.

4
Definition of Genetic Disorders

• A genetic disorder is an abnormal condition that
  a person inherits through genes or chromosomes

5
Causes of Genetic Disorders

• Some are causes by
• Mutation in the DNA of genes
• Changes in the overall structure or number of
  chromosomes

6
DNA Quick Review

• What is the structure of DNA?

7
Cause 1 Mutations

• Mutation
• Any change in a gene or chromosome
• Mutate means CHANGE!
• Mutations only affect us if they occur in SEX
  CELLS. . . Does not pass on if mutation is in
  body cell

8
Types of Mutations

• One nitrogen base pair may be substituted for
  another
• One nitrogen base pair is removed
• One base pair is added
• Chromosomes dont separate during meiosis

9
Pictures of Mutations in DNA

• Original
• Substitute
• Removed
• Added

10
Picture of Mutation in Chromosome

11
Cystic Fibrosis

• Body produces thick mucus
• Caused by recessive allele on a chromosome
• http//player.discoveryeducation.com/index.cfm?gui
  dAssetId7A00691D-2F20-4F66-BE08-663F290D4E7CblnF
  romSearch1productcodeUS

12
Sickle-Cell Disease

• http//www.youtube.com/watch?vujf72mjy0Bgfeature
  channel
• Disease affects hemoglobin
• protein in blood cells that carried oxygen
• When oxygen is low? cells are sickle-shaped
• This blocks blood vessels so oxygen cannot travel
  to cells
• Caused by
• presence of two defective genes that codes for
  hemoglobin (HBB gene)

13
Hemophilia

• Persons blood clots slowly or not at all
• Protein is not produced needed for normal
  clotting
• Caused by
• Recessive allele on X chromosome
• It is sex-linked so more common in males

14
Hemophilia Videos

• http//player.discoveryeducation.com/?blnPreviewOn
  ly1guidAssetIdeb0b8279-69cc-4fd4-a326-4d8d0797c
  bb3
• http//www.youtube.com/watch?v-aFcFqaOuyU

15
Down Syndrome

• http//www.youtube.com/watch?vbEVkbuooXo4
• Some degree of mental retardation and can be
  heart defects
• Caused by
• Extra copy of chromosome 21

16
How do we predict?

• What if you are having a child and you are
  worried about your child inheriting a genetic
  disorder?? What can you do to help you predict
  this?

17
Pedigrees

• Definition
• A pedigree is a chart or family tree that
  tracks which members of a family have an
  important trait
• Purpose
• This is a tool that geneticists use to trace the
  inheritance of traits in humans

18
Symbols

• SQUARE male
• CIRCLE female
• Half-shaded carrier of trait
• Empty does not have trait nor carries it
• Fully shaded person has trait

19
Pedigree Practice

• Analyze Pedigree in text
• www.phschool.com
• cep3042

20
Managing Genetic Disorders

• What if you have a disorder? What if your child
  will have a disorder? What do you do???

21
Managing Genetic Disorders

• Karotype
• Picture of all chromosomes in a cell
• Genetic Counseling
• Counselors can use tools to help predict
• Other
• Physical therapy
• Vitamins
• Training

22
Karyotypes

• Normal Female Turner Syndrome

23
Turner Syndrome

• Short
• Broad chest
• Poor breast development
• Visual impairments
• Ear infections/hearing loss
• Low set ears
• Many more symptoms

24
Videos

• Discovery

25
Pedigree Activity

• Page 156 in text
• Will work in pairs
• Prize. . .