Multiple Choice
In a typical eukaryotic cell cycle, how many major checkpoints are commonly described that regulate progression through the cycle?
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16. Cell Division
Control of the Cell Cycle
Multiple Choice
In eukaryotic cells, what molecular system primarily controls progression through the cell cycle at key checkpoints (e.g., G1/S and G2/M)?
A
Cyclin-dependent kinases (CDKs) activated by binding specific cyclins
B
Ribosomes that regulate checkpoint timing by controlling translation rate
C
DNA polymerases that directly trigger checkpoint passage when replication completes
D
Golgi-derived vesicles that signal completion of organelle duplication
Verified step by step guidance1
Understand that the cell cycle is regulated at specific checkpoints to ensure proper cell division, such as the G1/S checkpoint (entry into DNA synthesis) and the G2/M checkpoint (entry into mitosis).
Recognize that progression through these checkpoints is controlled by molecular complexes that can activate or inhibit the cell cycle machinery depending on internal and external signals.
Identify that Cyclin-dependent kinases (CDKs) are enzymes whose activity is regulated by binding to specific proteins called cyclins; this binding activates CDKs to phosphorylate target proteins that drive the cell cycle forward.
Note that other options like ribosomes, DNA polymerases, and Golgi-derived vesicles have different cellular roles and do not directly control checkpoint progression in the cell cycle.
Conclude that the primary molecular system controlling progression through the cell cycle at key checkpoints is the activation of CDKs by specific cyclins.
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