4.5.A—Describe the events that occur in the cell cycle

Describe the events that occur in the cell cycle.

• The cell cycle is a highly regulated series of events that controls the growth and reproduction of eukaryotic cells.
  • i. The cell cycle consists of sequential stages of interphase (G1, S, G2), mitosis, and cytokinesis.
  • ii. G1 phase: The cell is metabolically active, duplicating organelles and cytosolic components.
  • iii. S phase: DNA is in the form of chromatin and replicates to form two sister chromatids connected at a centromere.
  • iv. G2 phase: Protein synthesis occurs, ATP is produced in large quantities, and centrosomes replicate.
  • v. A cell can enter a stage (G0) in which it no longer divides, but it can reenter the cell cycle in response to appropriate cues.
  • vi. Nondividing cells may exit the cell cycle or be held at a particular stage in the cell cycle.