MCAT Basics (from MedSchoolCoach) The Cell Cycle
Jul 31, 2025
Delve into the fascinating world of the cell cycle! Discover the critical phases of interphase and mitosis, and learn how cells grow and prepare for division. Uncover the intricate regulation of the cycle through key checkpoints, particularly the role of the p53 protein in maintaining DNA integrity. The conversation also reveals how disruptions in these processes can lead to cancer, highlighting the importance of understanding cell behavior in disease context. Plus, explore intriguing links between growth hormones and cancer risk!
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Interphase Dominates The Cycle
- The eukaryotic cell cycle has two main phases: a long interphase and a short mitotic phase.
- Interphase (G1, S, G2) takes roughly 20 hours and mitosis about 2 hours in a typical 24-hour cycle.
G1 Is Quiet But Biochemically Active
- G1 is a growth phase where the cell increases proteins, nucleotides, organelles, mitochondria, and ribosomes.
- Microscopically it looks inactive, but major biosynthesis prepares the cell for DNA replication.
Pause Before S If DNA Is Damaged
- Cells can pause in G1, enter G0, or proceed to S depending on readiness and DNA integrity.
- Check for DNA damage before S to avoid replicating mutations that could seed tumors.
