Which of these checkpoints determines if cell division has occurred properly?

• A. G2 checkpoint
• B. S checkpoint
• C. M checkpoint
• D. G1 checkpoint

Answer: (C)

Verified step by step guidance

1. Understand the role of cell cycle checkpoints: Cell cycle checkpoints are control mechanisms in eukaryotic cells which ensure proper division of the cell. They help prevent the division of cells that have DNA damage or other issues.
2. Identify the different checkpoints: The main checkpoints in the cell cycle are the G1 checkpoint, S checkpoint, G2 checkpoint, and M checkpoint.
3. Clarify the function of each checkpoint: The G1 checkpoint checks for cell size, nutrients, growth factors, and DNA damage. The S checkpoint ensures that DNA replication has occurred correctly. The G2 checkpoint checks for DNA damage after replication and ensures all DNA is replicated. The M checkpoint, also known as the spindle checkpoint, ensures that all chromosomes are properly aligned and attached to the spindle before anaphase begins.
4. Focus on the M checkpoint: The M checkpoint is crucial for determining if cell division has occurred properly because it ensures that all chromosomes are correctly attached to the spindle apparatus, preventing chromosome missegregation.
5. Conclude with the correct checkpoint: Based on the functions of each checkpoint, the M checkpoint is responsible for ensuring that cell division has occurred properly, as it checks the alignment and attachment of chromosomes during mitosis.