1. Karyotypes & Chromosomal Abnormalities

2. Critical Thinking Practice Image Analysis – Cell Division
Write down five observations about the image below.
Name the phase AND type of cell division shown in the diagram. Explain how you know using your observations as evidence.

3. Karyotyping
A Karyotype is a picture of real chromosomes arranged in homologous pairs
Scientists or doctors take photos of a cell during division and “unscramble” the chromosomes using computer software

4. Two Types of Chromosomes
Sex Chromosomes
Determine the sex of the organism
Typical human male: X Y
Typical human female: X X
1 pair in humans
Autosomes
All other chromosomes
22 pairs in humans

5. Typical Human Karyotypes
Male
Female

6. Chromosomal Disorders
In nondisjunction chromosomes do not separate properly during meiosis; changes the final number of chromosomes
Trisomy – 3 copies of a chromosome (1 extra)
Monosomy – 1 copy of a chromosome (1 less)

7. Chromosomal Disorders

8. Chromosomal Disorders
Male or female?
Typical or atypical?
What kind of abnormality has occurred?
Trisomy 21 (Down Syndrome)

9. Chromosomal Disorders
Structural mutations affect chunks of chromosomes but do not change the total chromosome number
Deletion – loss of a chunk of chromosome
Duplication – many extra copies of chunk
Inversion – direction of chunk reversed
Translocation – chunk breaks off and relocates to a NON-homologous chromosome
Often difficult or impossible to see on a karyotype!

10. Chromosomal Disorders Pamphlet
Work in pairs to create a pamphlet or poster for a chromosomal disorder.
Each pamphlet/poster must have:
Name of the disorder
A description of the structural mutation or nondisjunction that causes the disorder
Symptoms of the disorder
At least 5 additional facts about the disorder
At least 2 images
Sources cited on back
Down Syndrome
Cri du Chat
Turner’s Syndrome
Fragile X
Klinefelter Syndrome
Patau Syndrome
Edward’s Syndrome