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D2.1.7—Phases of mitosis

Mitosis proceeds through prophase, metaphase, anaphase and telophase, separating sister chromatids into genetically identical nuclei during cell division events accurately.

Syllabus
First assessment 2025
Objective
D2.1.7
Level
HL

Exam analysis

Chance of appearing8%of analysed past papers
Latest appearanceMay 2022
Most common paperPaper2
Typical marks1–2

Common command terms

  • State
  • Identify
  • Outline
  • Describe
  • Deduce
  • Evaluate
  • Suggest
  • Label

Scoring notes

Common mistake
Confusing metaphase alignment with anaphase separation in micrographs.

Recent exam appearances

May 2022Paper2 ["HL"] · TZ22(a)(i)[ 2 ]D2.1.7—Phases of mitosis
May 2021Paper2 ["HL"] · TZ11(e)[ 3 ]D2.1.7—Phases of mitosis
May 2021Paper2 ["HL"] · TZ11(c)[ 2 ]D2.1.7—Phases of mitosis
November 2020Paper2 ["HL"] · TZ02(b)[ 2 ]D2.1.7—Phases of mitosis
May 2019Paper2 ["HL"] · TZ22(a)(i)[ 1 ]D2.1.7—Phases of mitosis
Practice this objective

Coverage 2012–2022 · Updated 16 Jul 2026

Mitosis Moves Chromosomes Through Four Main Stages

Mitosis proceeds through prophase, metaphase, anaphase and telophase, each solving a different chromosome-distribution problem.

Chromosomes condense and attach to spindle fibers, align at the equator, separate sister chromatids and re-form nuclei at opposite poles. Cytokinesis follows.

Use the sequence: condense; align; separate chromatids; rebuild nuclei.

A metaphase cell has chromosomes aligned at the equator; anaphase begins when sister chromatids move apart.

Interphase is not a mitosis stage, although it prepares the cell by growing and replicating DNA.

Phases of mitosis

Assessment in practice

1–2 marks
How it is assessed

This objective is assessed through structured response, commonly using State / Identify / Outline.

Command terms

State / Identify / Outline / Describe / Deduce / Evaluate / Suggest / Label

What earns marks

Build the answer around this relationship: Prophase condenses chromosomes and begins nuclear-envelope breakdown.

Watch for

Confusing metaphase alignment with anaphase separation in micrographs.

Representative question

Question 1

[Maximum number: 9]

Describe the events that occur during mitosis.

Core Cell Division

  • Cell division produces daughter cells for growth, repair or reproduction; cytokinesis divides cytoplasm by a contractile ring in animals or a cell plate in plants.
  • DNA replication creates sister chromatids joined at centromeres before nuclear division.
  • Mitosis preserves chromosome number: chromosomes condense, align, sister chromatids separate and nuclei reform, producing genetically identical nuclei.
  • Meiosis follows one replication with two divisions: homologous chromosomes separate in meiosis I and sister chromatids in meiosis II, producing haploid cells.
  • Crossing over, independent orientation and random fertilization generate allele combinations.
  • Non-disjunction is failed chromosome separation and can produce aneuploid cells, including trisomy 21.
  • Identify stages in micrographs from chromosome condensation, equatorial alignment, separation and nuclear-envelope cues.

Concept essentials

  • Prophase condenses chromosomes and begins nuclear-envelope breakdown.
  • Metaphase aligns chromosomes at the equator.
  • Anaphase separates sister chromatids to opposite poles.
  • Telophase reforms nuclei around separated chromosome sets.
  • Mitosis produces genetically identical nuclei by separating replicated chromatids.
ConceptIB Biology HL