Before You Begin
Question #45837
The Question
A geneticist analyzing a pedigree for an X-linked recessive disorder notes that a carrier female experienced a prolonged 24-month period of secondary amenorrhea and inability to conceive following her first delivery. While initially suspected to be a genetic anomaly causing sterility, it was confirmed she was practicing intense, exclusive breastfeeding. Regarding the physiological mechanism of this lactational amenorrhea that created this observational bias, which of the following statements is INCORRECT?
Options
- A.
High circulating levels of prolactin actively suppress the secretion of Gonadotropin-Releasing Hormone (GnRH) from the hypothalamus.
- B.
The absence of a corpus luteum during this period is due to the failure of the anterior pituitary to release adequate LH and FSH.
- C.
Prolactin directly maintains the corpus luteum from the previous pregnancy to continuously secrete progesterone, thereby inhibiting endometrial sloughing.
- D.
The resulting suppression of the Hypothalamic-Pituitary-Ovarian (HPO) axis creates a temporary phenocopy of infertility, delaying the transmission of the X-linked allele.
Check Your Answer
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
Lactational Amenorrhea Logic|Placental Endocrine Profile|Pedigree Analysis Traps
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students frequently confuse the mechanism of pregnancy maintenance (where hCG maintains the corpus luteum to secrete progesterone) with the mechanism of lactational amenorrhea.
The trap relies on the misconception that amenorrhea always requires high progesterone to prevent endometrial sloughing, whereas in lactational amenorrhea, the lack of menses is due to a complete shutdown of the HPO axis and subsequent lack of follicular estrogen to build the endometrium in the first place.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Pedigree Analysis Traps |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |