What are two factors that regulate the timing of the cell cycle?

Cyclins and regulatory proteins. Regulatory proteins include internal regulators and external regulators.

any of a number of proteins associated with the cycle of cell division which are thought to initiate certain processes of mitosis.

egulatory protein. regulatory protein (gene-regulatory protein) Any protein that influences the regions of a DNA molecule that are transcribed by RNA polymeraseduring the process of transcription. These proteins, which include transcriptionfactors, therefore help control the synthesis of proteins in cells.

synapse nervous system