Chromosomal Disorders - Down's, Turner's, Klinefelter's Syndrome - Unsolved Practice Set
Chapter: Principles of Inheritance and Variation | Topic: Chromosomal Disorders Downs Turners Klinefelters
CHROMOSOMAL DISORDERS - DOWN'S, TURNER'S, KLINEFELTER'S SYNDROME - UNSOLVED PRACTICE SET
Topic: Chromosomal Disorders Downs Turners Klinefelters
Multiple Choice Questions
Q1. Down syndrome is caused by the presence of an extra copy of chromosome number:
- 13
- 18
- 21
- 23
Q2. Klinefelter syndrome in humans is characterised by the chromosomal composition:
- 45, X
- 47, XXY
- 47, XXX
- 46, XY
Q3. The main cellular event responsible for most cases of aneuploidy, such as Down syndrome, is:
- Point mutation
- Non-disjunction of chromosomes during meiosis
- Crossing over
- Random fertilisation only
Q4. Turner syndrome in females is characterised by the chromosomal composition:
- 47, XXX
- 47, XXY
- 45, X (monosomy of X)
- 46, XY
Q5. Down syndrome, Klinefelter syndrome, and Turner syndrome are all examples of:
- Gene mutations
- Chromosomal (numerical) disorders
- Sex-linked recessive disorders
- Codominant disorders
Short Answer Questions
Q6. What is aneuploidy? Give one example of a human disorder caused by it.
Q7. Mention any two physical or developmental features associated with Down syndrome.
Q8. Briefly describe the chromosomal basis of Klinefelter syndrome.
Q9. What is non-disjunction, and how is it related to chromosomal disorders like Down syndrome?
Long Answer Questions
Q10. Explain the chromosomal basis, and describe the general characteristics, of Down syndrome in humans.
Q11. Compare Klinefelter syndrome and Turner syndrome in terms of their chromosomal composition and general features.
APPLICATION / ANALYSIS
Q12. A genetic counsellor explains to an expecting couple that the risk of Down syndrome increases with increasing maternal age. Using your understanding of non-disjunction, suggest a possible biological reason why this risk rises as the mother gets older.
Q13. A newborn is found to have the chromosomal composition 47, XXY upon genetic testing. Identify the disorder this chromosomal pattern corresponds to, and explain, based on the type of chromosomal error involved, how such an extra chromosome could have arisen during gamete formation.