Biology  by Bradford
IB Biology 2025 · Theme D · Continuity and change

D2.1 Cell and nuclear division. Practice questions with markscheme.

46 original IB-style questions on D2.1, written from the 2025 guide: 20 multiple-choice, 15 short-answer, 4 data-based, 3 extended-response part, 3 drawing, 1 labelling. Below is a 22-mark standard-level practice paper built from them, ready to hand out as a class quiz or homework, or to sit yourself and mark against the scheme. Print it, project it, or build a fresh one on the same topic.

What the guide asks for

11 statements at SL and HL, 6 additional higher level.

  1. D2.1.1SL / HL Generation of new cells in living organisms by cell division
  2. D2.1.2SL / HL Cytokinesis as splitting of cytoplasm in a parent cell between daughter cells
  3. D2.1.3SL / HL Equal and unequal cytokinesis
  4. D2.1.4SL / HL Roles of mitosis and meiosis in eukaryotes
  5. D2.1.5SL / HL DNA replication as a prerequisite for both mitosis and meiosis
  6. D2.1.6SL / HL Condensation and movement of chromosomes as shared features of mitosis and meiosis
  7. D2.1.7SL / HL Phases of mitosis
  8. D2.1.8SL / HL Identification of phases of mitosis
  9. D2.1.9SL / HL Meiosis as a reduction division
  10. D2.1.10SL / HL Down syndrome and non-disjunction
  11. D2.1.11SL / HL Meiosis as a source of variation
  12. D2.1.12HL Cell proliferation for growth, cell replacement and tissue repair
  13. D2.1.13HL Phases of the cell cycle
  14. D2.1.14HL Cell growth during interphase
  15. D2.1.15HL Control of the cell cycle using cyclins
  16. D2.1.16HL Consequences of mutations in genes that control the cell cycle
  17. D2.1.17HL Differences between tumours in rates of cell division and growth and in the capacity for metastasis and invasion of neighbouring tissue

In the bank for D2.1

  • 20 multiple-choice
  • 15 short-answer
  • 4 data-based
  • 3 extended-response part
  • 3 drawing
  • 1 labelling
  • 17 higher level only

Every question is original and tagged to a guide statement. See the whole bank →

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The practice paper

Take it on screen → Build a fresh paper Paper code BbB-EAAAAACAABQAO8f_
Biology · topic quiz
Standard level · topic practice, not an exam format
35 minutes22 marks

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Covers D2.1 Cell and nuclear division
Name:
1.

In which stage are sister chromatids being separated?

[1]
CEAFBDSix stages of meiosis in a cell with 2n = 4, not in order. Maternal chromosomes green (solid), paternal pink (dashed).
  1. A
  2. B
  3. C
  4. E
2.

Which statement about the division of cytoplasm (cytokinesis) is correct?

[1]
  1. The cytoplasm is always divided exactly equally
  2. Only the daughter cell that divides again needs mitochondria
  3. Division is usually equal, but yeast buds and oocytes are not
  4. Unequal cytokinesis occurs only in prokaryotic cells
3.

How does cytokinesis differ between plant and animal cells?

[1]
  1. Both animal and plant cells pinch in two by a cleavage furrow
  2. Plant cells pinch in two by a cleavage furrow; animal cells build a cell plate
  3. Animal cells form a cleavage furrow, whereas plant cells build a cell plate
  4. Plant cells do not divide their cytoplasm because the wall prevents it
4.

How can non-disjunction in meiosis lead to Down syndrome (trisomy 21)?

[1]
  1. Crossing over duplicates chromosome 21 in one of the gametes
  2. A gamete with two copies of chromosome 21 is fertilized by a normal gamete
  3. A mutation converts another chromosome into a copy of chromosome 21
  4. One copy of chromosome 21 is lost from the embryo after fertilization
5.

During which phase of mitosis do sister chromatids separate and move to opposite poles?

[1]
  1. Anaphase
  2. Telophase
  3. Metaphase
  4. Prophase
6.

Condensation and movement of chromosomes occur in both mitosis and meiosis. Outline how chromosomes are condensed and how they are then moved.

[3]
7.

A student examines dividing cells in a root tip and records descriptions of two cells.
Cell 1: chromosomes lined up in a single plane across the middle of the cell, each attached to spindle microtubules.
Cell 2: two groups of chromosomes at opposite ends of the cell, with nuclear envelopes re-forming around each group.

(a)Identify the phase of mitosis shown by each cell.[2]
(b)Outline what will happen next in cell 1.[2]
(c)State what the genetic result of this division will be.[1]
8.

The drawings show six stages of meiosis in a cell with 2n = 4, labelled A to F but not in the order in which they occur.

CEAFBDSix stages of meiosis in a cell with 2n = 4, not in order. Maternal chromosomes green (solid), paternal pink (dashed).
(a)State the order in which the stages occur, using the letters.[1]
(b)Identify the stage in which the chromosome number is halved, and explain why it is halved at this stage.[2]
(c)Explain how the events in stages C and E contribute to genetic variation.[2]
9.

Compare and contrast mitosis and meiosis.

[4]

Original practice questions © Biology by Bradford · CC BY-NC-SA 4.0 · Not affiliated with or endorsed by the International Baccalaureate Organization.
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Markscheme BbB-EAAAAACAABQAO8f_

One mark per point; / separates alternative wording within a point, OR separates alternative answers, words in brackets are not required, underlined words are essential. OWTTE = or words to that effect.

1. D2.1.9 [1]
  • B: in stage B (anaphase II) single chromatids are moving to opposite poles; in stage A (anaphase I) whole chromosomes, still made of two chromatids, are separated;
2. D2.1.3 [1]
  • C: equal division is the norm, but yeast buds and human oocytes (versus polar bodies) show unequal division; every viable daughter cell must still receive at least one mitochondrion;
3. D2.1.2 [1]
  • C: animals: actin/myosin ring pulls the membrane inward; plants: vesicles build a cell plate that becomes the new wall (the rigid wall prevents furrowing);
4. D2.1.10 [1]
  • B: failure of separation (anaphase I or II) gives an n+1 gamete; the zygote then carries three copies of chromosome 21;
5. D2.1.7 [1]
  • A: anaphase: centromeres split and spindle microtubules pull the (now) chromosomes apart; metaphase aligns them at the equator;
6. D2.1.6 [3 max]
  • the DNA is wrapped around histones (nucleosomes) and then coiled/supercoiled further, making the chromosomes shorter and thicker (condensation, visible by prophase);
  • spindle microtubules (growing from the poles) attach to the chromosomes at their centromeres;
  • (at anaphase) the microtubules shorten, pulling the chromosomes/chromatids to opposite poles;
  • (these shared features occur in mitosis and in both divisions of meiosis), OWTTE;
7. D2.1.7-D2.1.8
  • (a) [2]
    • cell 1, metaphase;
    • cell 2, telophase;
  • (b) [2]
    • the centromeres divide and sister chromatids separate (anaphase);
    • spindle microtubules pull the (daughter) chromosomes to opposite poles;
  • (c) [1]
    • two (daughter) nuclei/cells genetically identical to the parent (same diploid chromosome number);
8. D2.1.9, D2.1.11
  • (a) [1]
    • C, E, A, F, B, D;
  • (b) [2]
    • A (anaphase I);
    • homologous chromosomes (of each bivalent) are separated to opposite poles, so each cell receives one chromosome of each pair, OWTTE;
  • (c) [2]
    • stage C (prophase I): crossing over exchanges sections between non-sister chromatids, giving new combinations of alleles on a chromosome;
    • stage E (metaphase I): random orientation of bivalents means maternal and paternal chromosomes of different pairs assort independently into the gametes;
9. D2.1.4 [4 max]
  • both are forms of nuclear division / both are preceded by DNA replication (S phase);
  • both involve spindle microtubules moving chromosomes (through similar phases);
  • mitosis has one division, whereas meiosis has two;
  • mitosis produces two cells, whereas meiosis produces four;
  • mitotic daughter cells are diploid/same ploidy as the parent, whereas meiotic cells are haploid (half);
  • mitotic cells are genetically identical, whereas meiotic cells differ (crossing over, random orientation);
  • mitosis serves growth/repair/asexual reproduction, whereas meiosis makes gametes/spores for sexual reproduction;

Credit only explicitly comparative points for differences; award converse.

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