Grade_10_-_03-_12th_and_13th

Cell Division: Mitosis

• Introduction

  • Overview of mitosis process.

  • Importance of mitosis in cell division.

• Stages of Mitosis

  • Interphase

  • Prophase

  • Metaphase

  • Anaphase

  • Telophase

• Importance of Mitosis

  • Essential for growth, repair, and maintenance of cells.

• Understanding Cancer

  • Role of mitosis in tumor formation and cancer development.

The Cell Cycle

• Total Duration: Approximately 24 hours

  • G phase: 8-10 hours

  • S phase: 6-8 hours

  • G1, S, G2 phases make up interphase.

  • Mitotic (M) phase is relatively shorter.

Interphase Breakdown

• G1 Phase

  • Active cell growth, metabolic activity.

  • Duplicates organelles and cytosolic components.

  • Cells may exit cycle and become non-dividing.

• S Phase

  • DNA replication occurs.

  • Chromosomes duplicate (identical copies are made).

• G2 Phase

  • Continued growth and synthesis of proteins and enzymes.

  • Final preparations for mitosis (replication of centrosomes).

Stages of Mitosis

Prophase

• Chromosome Visibility

  • Individual chromosomes become visible.

• Nuclear Changes

  • Nuclear membrane and nucleolus disintegrate.

• Centrioles Movement

  • Animal cells: centrioles move to opposite poles.

  • Plant cells: spindle fibers form in cytoplasm.

Metaphase

• Alignment of Chromosomes

  • Chromosomes line up along the center (equator) of the cell.

  • Each chromosome is attached to spindle fibers via its centromere.

Anaphase

• Separation of Chromatids

  • Chromatids are pulled to opposite poles.

  • Now referred to as daughter chromosomes.

Telophase

• Chromosome Separation

  • Daughter chromosomes reach the poles.

  • Chromatin uncoils and nuclear membranes reform.

Cytokinesis

• Process of Cytoplasm Division

  • Not an official part of mitosis, follows it.

  • In animal cells: cell membrane constricts.

  • In plant cells: a cell plate forms.

• Outcome

  • Results in two genetically identical daughter cells.