Mitosis Phases Overview

Mitosis Phases

• Prophase

  • Chromatin condenses into visible chromosomes.
  • Each chromosome consists of two sister chromatids.
  • The nuclear envelope begins to disintegrate.
  • Spindle fibers form from the centrosomes and attach to kinetochores on chromosomes.

• Metaphase

  • Chromosomes align along the metaphase plate (equatorial plane).
  • Spindle fibers are fully formed and attach to the centromeres of chromosomes.
  • Ensures proper separation during anaphase.

• Anaphase

  • Sister chromatids are pulled apart towards opposite poles of the cell.
  • Spindle fibers shorten, ensuring chromatids move to each pole.

• Telophase

  • Chromatids reach the poles and begin to decondense back into chromatin.
  • Nuclear envelopes reform around each set of chromosomes.
  • Spindle apparatus disassembles.

• Cytokinesis

  • Division of the cytoplasm occurs after telophase.
  • In animal cells, a cleavage furrow forms; in plant cells, a cell plate forms.
  • Results in two separate daughter cells, each with a nucleus.

Cell Cycle Phases

• G1 Phase (Gap 1)

  • Cell grows and synthesizes proteins and organelles.
  • Prepares for DNA replication.
  • Checks for DNA damage; if issues are found, the cell may enter G0 phase (quiescence).

• S Phase (Synthesis)

  • DNA replication occurs, resulting in two copies of each chromosome (sister chromatids).
  • Centromeres are also duplicated.

• G2 Phase (Gap 2)

  • Further growth occurs, and the cell prepares for mitosis.
  • DNA is checked for errors post-replication.
  • Organelles are duplicated, and proteins necessary for mitosis are synthesized.

Mitosis Phases

• Prophase: Chromatin condenses into visible chromosomes with two sister chromatids each; nuclear envelope disintegrates; spindle fibers form from centrosomes and attach to kinetochores.
• Metaphase: Chromosomes align at the metaphase plate; spindle fibers fully formed, attaching to centromeres; ensures accurate distribution of chromatids.
• Anaphase: Sister chromatids are separated and pulled to opposite cell poles; spindle fibers shorten to facilitate movement.
• Telophase: Chromatids reach cell poles, begin to revert to chromatin; nuclear envelopes reform around each chromosome set; spindle apparatus disassembles.
• Cytokinesis: Cytoplasmic division follows telophase; in animal cells, cleavage furrow forms; in plant cells, a cell plate forms; results in two daughter cells, each with a nucleus.

Cell Cycle Phases

• G1 Phase (Gap 1): Cell undergoes growth, synthesizes proteins and organelles; prepares for DNA replication; DNA damage checkpoints may prompt entry into G0 phase (quiescence).
• S Phase (Synthesis): Critical for DNA replication; results in sister chromatids, with centromeres duplicated for proper division.
• G2 Phase (Gap 2): Continues cell growth, preparing for mitosis; DNA integrity is checked post-replication; organelles duplicate, and mitosis-related proteins are synthesized.

This quiz covers the key phases of mitosis, including prophase, metaphase, anaphase, telophase, and cytokinesis. Each phase is crucial in understanding the process of cell division and the role of chromosomes. Test your knowledge on these vital cellular processes.