Summary of The Cell Cycle and Cell Division

The Cell Cycle Overview

  • The cell cycle includes growth, development, and division of cells.

  • Interphase (90% of lifespan): cellular growth and DNA replication occur.

    • G1: Cell growth

    • S: DNA synthesis

    • G2: Preparation for mitosis

  • Mitosis (10% of lifespan): division of nucleus and cytoplasm; results in two identical daughter cells.

Mitosis Stages

  • Prophase: Chromatin condenses into chromosomes; nucleolus disappears and spindle fibers form.

  • Metaphase: Duplicated chromosomes align at the cell's center.

  • Anaphase: Sister chromatids separate and move to opposite poles.

  • Telophase: Chromosomes uncoil, nuclear membranes reform around each set.

  • Cytokinesis: Cytoplasm divides; in animal cells, membrane pinches; in plant cells, a cell plate forms.

Cell Cycle Duration

  • Duration varies by cell type: human cells typically cycle in 24 hours; some may take much longer or not divide.

  • Organelle replication occurs prior to division, ensuring that each daughter cell receives necessary structures.

Key Conclusions

  • The cell cycle is vital for reproduction, growth, and tissue repair.

  • Each daughter cell is genetically identical to the original cell, ensuring genetic continuity.