Which checkpoint in the eukaryotic cell cycle ensures that all chromosomes are properly bi-oriented and attached to the mitotic spindle before triggering anaphase onset?
Answer and explanation
Correct answer: C. Spindle assembly checkpoint (M checkpoint)
- Step 1: To avoid aneuploidy, a dividing cell must verify that every single kinetochore has captured spindle microtubules from opposite poles.
- Step 2: The Spindle Assembly Checkpoint (SAC or M checkpoint) senses unattached kinetochores and generates an inhibitory signal (via Mad2 and BubR1).
- Step 3: This signal inhibits the anaphase-promoting complex (APC/C), delaying anaphase until tension across all kinetochores confirms proper alignment.
Answer
Spindle assembly checkpoint (M checkpoint).
Why not the others: restriction point assesses growth factors, cell size, and DNA integrity before committing to replication; checkpoint ensures DNA replication is complete and undamaged; Cytokinesis checkpoint monitors furrow progression.
Practise more Cell Cycle and Cell Division.
Free questions with an explanation for every one, and full timed NEET UG mock tests.
More Cell Cycle and Cell Division questions
- During which phase of the eukaryotic cell cycle does DNA replication occur, doubling the DNA content from to while k…
- In which substage of meiotic Prophase I does crossing over (genetic recombination) occur between non-sister chromatids of homologous chromos…
- The X-shaped structures formed at the sites of crossing over between homologous chromosomes become clearly visible during which stage of Pro…
- What occurs during Anaphase I of meiosis that fundamentally differs from mitotic Anaphase?
- During which mitotic phase do chromosomes align along the equatorial plane of the spindle, making it the most suitable stage to study chromo…
- In animal cells, the division of cytoplasm (cytokinesis) is accomplished by: