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Question #45514
The Question
The incidence of aneuploid conditions, such as Down syndrome, increases significantly with advanced maternal age. This is primarily attributed to a structural vulnerability in the female gametogenic process that is absent in continuous male spermatogenesis. Which of the following accurately identifies this vulnerability and its genetic consequence?
Options
- A.
Prolonged arrest of primary oocytes in Prophase I makes them highly susceptible to the non-disjunction of homologous chromosomes during Anaphase I.
- B.
Arrest of secondary oocytes in Metaphase II increases the risk of non-disjunction of sister chromatids if fertilization is delayed.
- C.
Post-natal mitotic division of oogonia accumulates genetic errors over decades, leading to unequal chromosomal distribution during Meiosis I.
- D.
Extensive follicular atresia during the reproductive phase degrades the spindle apparatus, inducing non-disjunction in the surviving secondary oocytes.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Ovarian Follicle Stages|Chromosomal Theory of Inheritance|Non-disjunction
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the two meiotic arrests in oogenesis (Prophase I vs.
Metaphase II) and linking the extreme duration of the Prophase I arrest to the mechanical failure of chromosome segregation (non-disjunction).
Students often confuse the Metaphase II arrest (which is broken by sperm entry) with the Prophase I arrest (which is responsible for age-related genetic risks like Trisomy 21).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Reproduction - Class 12 |
| Concept | Ovarian Follicle Stages |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |