Speed up or slow down the cell cycle are functions of external regulators of the cell cycle.
The regulation of cell proliferation, growth and DNA synthesis are controlled by the regulatory machinery of the cell cycle.
Cell cycle progression is activated directly by a series of heterodimers formed by cyclins and cyclin-dependent kinases (CDKs).
- Cyclin D, by forming a complex with the cyclin-dependent kinases CDK4, activates the action of the kinase whose main substrate is the Rb protein.
- Cyclin D are proteins that respond to external signals in cells and execute responses such as acceleration of the cell cycle.
- Cyclin D1 is a protein encoded by the CCND1 gene this acts on the cell cycle by accelerating the G1 phase.
- In the hypophosphorylated state, the Rb tumor suppressor protein is active and performs its function by inhibiting cell cycle progression.
Therefore, we can conclude that speed up or slow down the cell cycle are functions of external regulators of the cell cycle.
Learn more here: https://brainly.com/question/22558385
