Explain how cytokinesis differs between animal cells and plant cells.

IB DP Biology Standard Level (2023 syllabus) — D2.1 Cell and nuclear division · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

In animal cells cytokinesis is achieved by the formation of a cleavage furrow. A contractile ring of actin microfilaments and myosin pulls the plasma membrane inward, creating a deepening furrow that eventually pinches the cell into two.

In plant cells cytokinesis occurs by the formation of a cell plate. Golgi‑derived vesicles carrying cell‑wall materials (cellulose, pectin, etc.) fuse at the centre of the cell, forming a new membrane that expands outward until it fuses with the existing plasma membrane, giving rise to a new cell wall that separates the two daughter cells.

Examiner tips

Mention the cleavage furrow and contractile ring for animals; mention the cell plate and Golgi vesicles for plants.
Use the exact terms "cleavage furrow", "actin microfilaments", "cell plate", "Golgi-derived vesicles".
Show the difference in mechanism (inward pulling vs outward growth).

Common mistakes

Confusing the plant mechanism with a furrow; describing a furrow in plant cells.
Using "microtubules" instead of actin for the animal contractile ring.
Omitting the role of Golgi vesicles or cell‑wall materials in plant cytokinesis.

Mark scheme (4 marks)

In animal cells, cytokinesis occurs by cleavage / formation of a cleavage furrow
The cleavage furrow is formed by a contractile ring of actin (micro)filaments pulling the membrane inward
In plant cells, cytokinesis occurs by formation of a cell plate in the centre of the dividing cell
The cell plate is formed from Golgi-derived vesicles containing cell wall materials (cellulose / polysaccharides) and eventually becomes the new cell wall / plasma membrane dividing the two daughter cells

Key terms in this question

cytokinesis