Question

Which of the following monitors of cells progress from face-to-face during the cell cycle?

A. A series of enzymes
B. Microtubules
C. Molecules
D. Protein molecules

Answer 1

Cell progress through the cell cycle is monitored by molecules, chiefly cyclins and cyclin-dependent kinases, which regulate checkpoints and ensure proper conditions for the cell to move to the next stage.

Step-by-step explanation:

The components that monitor a cell's progress through the cell cycle are a variety of molecules, particularly cyclins and cyclin-dependent kinases (Cdks). These molecules ensure that a cell only progresses to the next stage of the cell cycle once specific conditions are met. Cyclins regulate the progress by fluctuating in concentration during the cell cycle, rising to trigger progression to a new stage and being degraded after their job is done. Cyclin/Cdk complexes fully activate to allow the cell cycle to proceed through checkpoints. However, certain mechanisms, including Cdk inhibitors, can halt the cycle if problematic conditions arise and will prevent the full activation of Cdks until the specific monitored event is completed.