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Question #45850
The Question
A sterile human male exhibits overall masculine development accompanied by gynecomastia. Karyotype analysis reveals a 47, XXY chromosomal complement. Which of the following statements regarding the meiotic origin and physiological consequences of this disorder is INCORRECT?
Options
- A.
The condition can arise from the fertilization of a normal ovum (22+X) by an abnormal sperm (22+XY) generated due to non-disjunction during paternal Meiosis II.
- B.
The condition can arise from the fertilization of an abnormal ovum (22+XX), generated due to non-disjunction during maternal Meiosis I or II, by a normal sperm (22+Y).
- C.
The individual will exhibit elevated levels of pituitary gonadotropins (FSH and LH) due to impaired negative feedback from testicular hormones.
- D.
The somatic cells of this individual will display exactly one Barr body in the nucleus during interphase.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Down/Klinefelter/Turner Syndrome Karyotypes|Primary Oocyte|Homologous Chromosomes
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the products of Meiosis I vs Meiosis II non-disjunction in heterogametic males.
Students often memorize that Klinefelter is caused by 'non-disjunction' without mapping the specific meiotic stage.
The trap relies on the fact that because X and Y are homologous chromosomes (not sister chromatids), an XY sperm can ONLY result from a failure of homologous separation (Meiosis I), whereas XX or YY sperm result from sister chromatid failure (Meiosis II).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Down/Klinefelter/Turner Syndrome Karyotypes |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |