🧬 Topic Summary
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (meiosis or mitosis). This can result in daughter cells with an abnormal number of chromosomes (aneuploidy). Nondisjunction can occur during meiosis I or meiosis II in gamete formation, leading to genetic disorders such as Down syndrome (trisomy 21) or Turner syndrome (monosomy X).
Understanding nondisjunction is crucial for comprehending the origins of various genetic conditions and the importance of accurate chromosome segregation during cell division. This quiz will test your knowledge of the key concepts and processes involved in nondisjunction.
🔬 Part A: Vocabulary
Match the terms with their correct definitions:
| Term |
Definition |
| 1. Aneuploidy |
A. The failure of chromosomes to separate properly during cell division. |
| 2. Nondisjunction |
B. A condition in which a cell has an abnormal number of chromosomes. |
| 3. Trisomy |
C. A condition in which there is an extra copy of a chromosome. |
| 4. Monosomy |
D. A condition in which there is a missing copy of a chromosome. |
| 5. Meiosis |
E. A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell. |
🧪 Part B: Fill in the Blanks
Nondisjunction can occur during __________ I or __________ II of meiosis. If nondisjunction occurs during meiosis I, all resulting gametes will be __________. If nondisjunction occurs during meiosis II, __________ gametes will be normal and __________ will be abnormal. The result of nondisjunction is an imbalance in the number of __________ in the resulting cells.
🤔 Part C: Critical Thinking
Explain how nondisjunction during meiosis can lead to genetic disorders like Down syndrome. What specific chromosomal abnormality is associated with Down syndrome, and how does nondisjunction contribute to this condition?