1. Aim: How can we compare chromosome mutations & gene mutations? Chromosome Gene

2. Chromosome Mutation: Nondisjunction- occurs when homo- logous chromosomes or sister chromatids fail to separate during meiosis. Causes a change in chromosome number or structure.

3. Trisomy Vs Monosomy: 3 Copies of a Chromosome 1 copy of a homologous pair Trisomy 21 Monosomy X Down SyndromeTurner Syndrome

4. Down Syndrome

5. Turner’s Syndrome

6. What causes nondisjunction to occur? No one really knows for sure, but the older the age of the mother the greater the chance of having a child with Down Syndrome. Trisomy 21

7. Chromosome Damage: Part of a chromosome is repeated. Part of a chromosome is missing. Reversing a fragment of the chromosome. Rearrangement of parts between non- homologous pairs of chromosomes.

8. Gene Mutations: Are due to a change in a single gene. Can involve changes in several nucleotides

9. Genetic Diseases caused by gene mutations: Cystic Fibrosis Faulty gene produces a defective protein that does not allow for the proper removal of mucous lining the cells of the lung and GI tract.

10. Gene Mutations: Faulty gene produces a defective enzyme which cannot help remove fat from nerve cells. Tay-Sachs Disease

11. Sickle-Cell Anemia: One base is substituted for another and this causes the production of a distorted hemoglobin molecule (protein) which cannot function properly.

12. What do these three gene mutations have in common? They all affect the shape of proteins!! If we change the shape of proteins (enzymes) they will not function properly and this will affect our phenotype.