Checkpoint in the Cell Cycle

What is the significance of the M checkpoint in the cell cycle?

A cell has detected a problem: One of its chromosomes is not properly attached to a spindle fiber. The cell is at which checkpoint in the cell cycle?

OA. S checkpoint

B. G₂ checkpoint

OC. G₁ checkpoint

OD. M checkpoint

Answer:

The cell is at the M checkpoint in the cell cycle. The M checkpoint, also known as the spindle checkpoint or the metaphase checkpoint, plays a crucial role in ensuring the fidelity of chromosome segregation during cell division.

The M checkpoint is a critical step that occurs during mitosis, the process of cell division. This checkpoint specifically monitors the proper attachment of chromosomes to spindle fibers before the cell progresses to the next stage of division.

If a chromosome is not correctly connected to the spindle fiber at the M checkpoint, the cell cycle will be halted. This pause allows the cell to fix any issues with chromosome attachment before proceeding to chromosome segregation and ultimately cell division.

Proper regulation of the M checkpoint is essential for maintaining genomic stability and preventing errors in chromosome segregation that can lead to genetic abnormalities and diseases such as cancer. By ensuring that all chromosomes are properly aligned and attached to spindle fibers, the M checkpoint helps to safeguard the integrity of the cell's genetic material.

Understanding the significance of the M checkpoint in the cell cycle highlights the intricate mechanisms that cells utilize to ensure accurate chromosome segregation and faithful transmission of genetic information from one generation to the next.