Seen as quite offensive for some, especially older groups and British Asian females, with its sexual connotations. For others it is seen as a middle of the road sort of word. Most offensive word to majority, and never really acceptable (though some might occasionally use).
Cyclins go hand in hand with kinases. Cyclins do not cause a cell to progress in the cell cycle because cyclins are mere proteins that regulate the rate of the process, and how fast the cell progresses through this process. Cyclins also act by binding to various kinases, which are enzymes that transfer a phosphate group from ATP to other enzymes. The phosphate group activates these enzymes. The quantity of these kinases in the cell remains steady throughout the cell cycle; however they are active only when bound to cyclins.
Cyclin-dependent kinases drive each of the major cell cycle transition points (G1, S, G2, M), inducing downstream processes by phosphorylating select proteins. While CDK protein levels remain stable throughout the cell cycle, cyclin levels fluctuate and, in this way, periodically activate CDKs.