Before You Begin
Question #45284
The Question
In a mammalian spermatocyte, a targeted mutation completely inhibits the assembly of the synaptonemal complex during Prophase I. Assuming the cell bypasses cell cycle checkpoints and completes both meiotic divisions, which of the following is the most likely systemic consequence?
Options
- A.
A. Recombination nodules will form normally during pachytene, but the absence of synapsis will result in haploid gametes with no genetic variation.
- B.
B. The failure of bivalent stabilization will prevent reductional segregation, forcing a defective mitosis-like division that produces diploid or aneuploid gametes.
- C.
C. The cell will undergo a premature equational division during Anaphase I, resulting in four genetically identical haploid gametes.
- D.
D. Chiasmata will form during diplotene to hold the homologs together, but terminalization will fail, arresting the cell in Metaphase I.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Synaptonemal_Complex_Assembly|Equational_Division_Logic|Meiosis_I
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'Meiosis I is reductional' as an absolute rule.
The trap lies in failing to realize that the reductional nature of Meiosis I is mechanically dependent on the synaptonemal complex and chiasmata holding homologs together.
Without synapsis, the spindle apparatus cannot generate the bipolar tension required to separate intact homologous chromosomes, causing the cell to default to a defective equational (mitosis-like) division, which ultimately results in polyploidy or aneuploidy.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | Equational Division Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |