During cyclin synthesis, what happens to cyclin levels?

During cyclin synthesis, the levels of cyclin are indeed synthesized and degraded in cycles. Cyclins are regulatory proteins that are essential for the progression of cells through the cell cycle. Their production varies at specific phases of the cycle, correlating with the activation of cyclin-dependent kinases (CDKs) that regulate key transitions.

In detail, cyclins are synthesized during specific stages; for instance, cyclin D is synthesized during the G1 phase, while cyclin B is synthesized in preparation for mitosis. After they activate their corresponding CDKs, cyclins are also targeted for degradation to ensure that the cell cycle proceeds correctly and is not stuck in a particular phase. This cyclical pattern of synthesis and degradation allows for precise control of cell cycle progression. This behavior exemplifies the dynamic nature of cyclin levels as they rise and fall in a well-regulated manner, enabling proper cell function and division.