The transition from metaphase to anaphase in mitosis requires:

Cyclin B synthesis occurring continuously throughout the entirety of mitosis

Activation of CDK1 at the G 2 to M phase boundary without any further checkpoint regulation required afterward

Complete assembly of an entirely new mitotic spindle built independently at each subsequent round of division

The transition from metaphase to…

Answer: APC/C (anaphase-promoting complex) activation by Cdc20, degrading cyclin B and securin.

A Cyclin B synthesis occurring continuously throughout the entirety of mitosis
B APC/C (anaphase-promoting complex) activation by Cdc20, degrading cyclin B and securin
C Activation of CDK1 at the G<sub>2</sub> to M phase boundary without any further checkpoint regulation required afterward
D Complete assembly of an entirely new mitotic spindle built independently at each subsequent round of division

Correct answer: B. APC/C (anaphase-promoting complex) activation by Cdc20, degrading cyclin B and securin

Explanation: APC/C-Cdc20 ubiquitinates cyclin B (inactivating CDK1) and securin (releasing separase). Both are degraded by the proteasome, triggering anaphase.

The cell cycle: G₁ (growth and preparation), S (DNA replication, chromosome number stays 2n but DNA content doubles), G₂ (final checks before division), and M (mitosis itself) - together, G₁+S+G₂ make up interphase.

Concept context

Mitosis and meiosis: how cells divide for growth, repair, and reproduction.

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The transition from metaphase to anaphase in mitosis requires:

Concept context

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