Overview of Mitosis

Overview of Mitosis

• Mitosis is a type of cell division that results in two genetically identical daughter cells.
• It is essential for growth, repair, and asexual reproduction in organisms.
• Mitosis is a continuous process, but it is often described in phases for easier understanding.

Phases of Mitosis

• Prophase:

  • Chromatin condenses into visible chromosomes.
  • The nuclear envelope breaks down.
  • Spindle fibers begin to form.
  • Centrioles (in animal cells) move to opposite poles of the cell.

• Metaphase:

  • Chromosomes align along the equator (middle) of the cell.
  • Spindle fibers attach to the centromeres of each chromosome.

• Anaphase:

  • Sister chromatids separate and move towards opposite poles of the cell.
  • Spindle fibers shorten.

• Telophase:

  • Chromosomes reach opposite poles and begin to decondense.
  • Nuclear envelopes reform around each set of chromosomes.
  • Spindle fibers break down.
  • Cytokinesis begins.

Cytokinesis

• Cytokinesis is the division of the cytoplasm to form two separate daughter cells.
• In animal cells, a cleavage furrow forms and pinches the cell in two.
• In plant cells, a cell plate forms between the two nuclei, eventually developing into a new cell wall.

Importance of Mitosis

• Growth: Mitosis allows organisms to grow by increasing the number of cells.
• Repair: Damaged tissues can be repaired through mitosis, replacing dead or injured cells.
• Asexual Reproduction: Some organisms reproduce asexually through mitosis, creating genetically identical offspring.

Cellular Control of Mitosis

• A cell's control over mitosis is crucial to prevent uncontrolled cell growth, which can lead to cancer.
• Various checkpoints ensure that each step of mitosis is completed correctly and that the cell is ready to divide.

Interphase

• Interphase is the period of cell growth and development that precedes mitosis.
• It is not a part of mitosis but a crucial part of the cell cycle.
• During interphase, the cell grows, replicates its DNA (chromosomes), and carries out its normal cellular functions.

Difference between Mitosis in Animal and Plant Cells

• Animal cells have centrioles which initiate the formation of the spindle apparatus, unlike plant cells.
• Plant cells have a rigid cell wall, requiring the formation of a cell plate to divide the cytoplasm during cytokinesis, not a cleavage furrow as in animal cells.

Key Terms

• Chromosome: A condensed structure of DNA containing genetic information.
• Chromatid: One half of a duplicated chromosome.
• Centromere: The region where two sister chromatids are joined.
• Spindle Fibers: Protein structures that help separate chromosomes during mitosis.

Explore the process of mitosis, a crucial type of cell division that results in two genetically identical daughter cells. Learn about its phases, including prophase, metaphase, anaphase, and telophase. This quiz will help reinforce your understanding of cell division and its significance in growth and repair.