Directions

Question

Choose the correct answer for each row.

There are many disorders caused by gene and chromosomal mutations. Read each description of these genetic disorders and click to select which type of mutation causes it.

Gene Mutation

Chromosomal Mutation

Down's syndrome is caused by an extra copy of the 21st chromosome, resulting in 3 copies of chromosome #21 instead of 2 copies.

Cystic Fibrosis is passed from parent to child, causing thick, sticky mucus to be produced in the body. It is caused by a deletion of nucleotides in a single gene.

Klinefelter's Syndrome is found in males, and those affected have an extra copy of the "X" sex chromosome.

Tay-Sachs disease is caused by a defect in the 15th chromosome and gradually destroys the nervous system. This disease is caused by a combination of base substitutions, deletions, and insertions.

Duchenne's Muscular Dystrophy is caused by a frameshift mutation in a gene that controls the health of muscles and is passed down from the parent(s).

Answer 1

Here are the correct answers for each disorder description:

1. Down's syndrome - Chromosomal Mutation (an extra copy of chromosome 21)

2. Cystic Fibrosis - Gene Mutation (deletion of nucleotides in a single gene)

3. Klinefelter's Syndrome - Chromosomal Mutation (extra copy of the "X" sex chromosome)

4. Tay-Sachs disease - Gene Mutation (defect in a gene with base substitutions, deletions, and insertions)

5. Duchenne's Muscular Dystrophy - Gene Mutation (frameshift mutation in a gene)

To summarize:

• Down's syndrome: Chromosomal Mutation
• Cystic Fibrosis: Gene Mutation
• Klinefelter's Syndrome: Chromosomal Mutation
• Tay-Sachs disease: Gene Mutation
• Duchenne's Muscular Dystrophy: Gene Mutation