Questions: Question 9 of 15 The M phase checkpoint ensures that all chromosomes are attached to the mitotic spindle fibers does not happen cells would most likely be arrested in A. Anaphase B. Prophase C. G2 D. metaphase Question 10 of 15 Which of the following describes the most accurate during mitosis? A. Condensation of the chromosomes B. Replication of the DNA C. Separation of sister chromatids D. Spindle formation

Question 9 of 15

The M phase checkpoint ensures that all chromosomes are attached to the mitotic spindle fibers. If this does not happen, cells would most likely be arrested in:

The answer is D: metaphase.

Explanation:

• A. Anaphase: Incorrect. Anaphase is the stage where sister chromatids are pulled apart to opposite poles of the cell. If the chromosomes are not properly attached to the spindle fibers, the cell will not proceed to anaphase.
• B. Prophase: Incorrect. Prophase is the stage where chromosomes condense and the mitotic spindle begins to form. The M phase checkpoint does not act at this stage.
• C. G2: Incorrect. G2 is a phase in the cell cycle before mitosis begins. The M phase checkpoint specifically monitors events during mitosis, not during G2.
• D. Metaphase: Correct. The M phase checkpoint, also known as the spindle checkpoint, ensures that all chromosomes are properly attached to the spindle fibers before the cell proceeds to anaphase. If this checkpoint is not satisfied, the cell will be arrested in metaphase to prevent errors in chromosome segregation.

Question 10 of 15

Which of the following describes the most accurate event during mitosis?

The answer is C: Separation of sister chromatids.

Explanation:

• A. Condensation of the chromosomes: Incorrect. While chromosome condensation is an important event in mitosis, it is not the most defining feature of the process.
• B. Replication of the DNA: Incorrect. DNA replication occurs during the S phase of the cell cycle, not during mitosis.
• C. Separation of sister chromatids: Correct. The most critical and defining event of mitosis is the separation of sister chromatids, which ensures that each daughter cell receives an identical set of chromosomes.
• D. Spindle formation: Incorrect. Spindle formation is crucial for mitosis, but it is a preparatory step rather than the main event.

Summary: For Question 9, the cell would be arrested in metaphase if the M phase checkpoint is not satisfied. For Question 10, the most accurate description of an event during mitosis is the separation of sister chromatids.