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Mitosis Stage Explorer

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About This MicroSim

This interactive diagram shows the five stages of mitosis — Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis — in a single panoramic view. Each stage is shown as a separate cell with key structures labeled by numbered callout markers.

Use Explore mode to hover over any marker or label and read detailed descriptions of each structure, including AP Exam Tips for testable concepts.

Switch to Quiz mode to test your ability to identify mitotic structures by clicking the correct marker when prompted.

Structures by Stage

Prophase

  1. Condensing chromosomes — Chromatin coils into visible X-shaped sister chromatids
  2. Centrosomes with asters — Microtubule-organizing centers migrate to opposite poles
  3. Nuclear envelope breakdown — Lamina disassembles as CDKs phosphorylate lamins
  4. Disappearing nucleolus — rRNA transcription ceases and the nucleolus disperses

Metaphase

  1. Metaphase plate alignment — All chromosomes bi-orient at the cell equator
  2. Kinetochore microtubules — Spindle fibers attach to chromosome kinetochores from both poles
  3. Spindle assembly checkpoint — SAC ensures all kinetochores are properly attached before anaphase

Anaphase

  1. Sister chromatid separation — Separase cleaves cohesin; V-shaped chromatids move to poles
  2. Cell elongation — Polar microtubules slide apart, pushing the cell poles further away

Telophase

  1. Reforming nuclear envelopes — Membrane vesicles fuse around each chromosome set
  2. Chromosome decondensation — Condensed chromosomes relax back into diffuse chromatin
  3. Cleavage furrow — Cell surface indents at the former metaphase plate position
  4. Contractile ring — Actin-myosin belt constricts to pinch the cell in two

Cytokinesis

  1. Daughter cells — Two genetically identical diploid cells, each half the parent's size
  2. Restored interphase nuclei — Complete nuclei with decondensed chromatin; cells enter G1

How to Use

  1. Explore mode (default): Hover over any numbered marker or label to see a description and AP Exam Tip
  2. Quiz mode: Click the Quiz button — labels are hidden and you must click the correct marker for each prompted structure
  3. Edit mode: Open main.html?edit=true in a browser to drag markers and calibrate positions

Lesson Plan

Grade Level

9-12 (AP Biology)

Duration

10-15 minutes

Prerequisites

  • Basic understanding of the cell cycle (G1, S, G2, M phases)
  • Knowledge of chromosome structure (chromatids, centromeres)
  • Familiarity with the cytoskeleton (microtubules, microfilaments)

Activities

  1. Exploration (5 min): Students hover over all 15 structures in Explore mode, reading descriptions and AP tips for each stage
  2. Stage Comparison (5 min): Students identify which structures appear, disappear, or change between stages
  3. Quiz Assessment (5 min): Students complete the Quiz mode, identifying all 15 structures by clicking the correct marker

Assessment

  • Students should be able to name the 5 stages of mitosis in order
  • Students should identify at least 3 key events per stage
  • Students should explain the role of the spindle assembly checkpoint
  • Students should compare animal cell cytokinesis (cleavage furrow) with plant cell cytokinesis (cell plate)

References

  1. Mitosis - Wikipedia
  2. Cell Division - Khan Academy
  3. Campbell Biology, 12th Edition — Chapter 12: The Cell Cycle