Before You Begin
Question #45382
The Question
During early human embryogenesis, the trophoblast must undergo specific structural and functional changes for successful implantation. If a targeted mutation in a non-coding regulatory DNA sequence completely inhibits the expression of fusogenic proteins in the trophoblast, which of the following will be the most direct consequence?
Options
- A.
The blastocyst will fail to hatch from the zona pellucida due to the absence of lytic enzymes.
- B.
The cytotrophoblast cells will immediately cease mitotic proliferation, arresting overall blastocyst growth.
- C.
The formation of the multinucleated syncytiotrophoblast will be blocked, preventing endometrial invasion.
- D.
The inner cell mass will undergo compensatory differentiation to secrete human chorionic gonadotropin (hCG).
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
Syncytiotrophoblast|Non_Coding_Strand_Utility|Okazaki_Fragment_Logic
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question requires cross-chapter synthesis between 'Human Reproduction' (Implantation dynamics) and 'Molecular Basis of Inheritance' (Role of non-coding regulatory sequences).
The primary trap is functional confusion: students often view the trophoblast as a single, static layer rather than a dynamic tissue that must undergo cellular fusion (forming a syncytium) to achieve its invasive and endocrine (hCG secretion) functions.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Reproduction - Class 12 |
| Concept | Implantation and Syncytiotrophoblast |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |