Select the characteristics that are true of restriction points.Check all that apply.

Question

Quizplus · Accepted Answer

Restriction points are specific points in the cell cycle where the progression of the cycle is regulated. An example of a restriction point is the G₁/S checkpoint, which marks the boundary between G₁ and S phase. At this point, the cell must make a decision about whether to continue through the cell cycle or to exit the cycle and enter a quiescent state. Molecular changes, such as the activation of cyclin-dependent kinases (CDKs), often need to be present for the cell to pass through the restriction point. Once a cell passes a restriction point, it is committed to the next stage of the cell cycle, and cannot reverse to an earlier phase. Therefore, options A, B, and C are true for restriction points. Option D is incorrect because cells passing a restriction point cannot reverse to an earlier phase of the cell cycle.

Select the Characteristics That Are True of Restriction Points