A student investigating cell division found that cells in the meristems of plant roots divide more frequently than cells in other parts of the plant. Explain why cells in meristems are able to keep dividing, and describe what happens during the cell cycle to prepare a cell for division.

Eduqas A-Level Biology — 1.6 Cell division · Explain · 5 marks · View as Markdown

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

Meristems are regions found at the root and shoot tips of plants. Cells in meristems retain the ability to divide throughout the life of the plant, unlike most other plant cells which become specialised and lose this ability.

Model answer (5 marks)

Meristem cells are stem cells that remain unspecialised and retain the ability to differentiate into any cell type.

When a cell differentiates it loses this ability; specialised cells cannot divide to give rise to an unspecialised cell.

During the cell cycle, interphase precedes mitosis. In G1 the cell grows and organelles are produced. In S phase DNA is replicated, giving each chromosome two identical sister chromatids. In G2 the cell checks the DNA and prepares for division.

Mitosis then divides the nucleus, producing two daughter cells that each receive an identical copy of the DNA and the same number of organelles, maintaining the cell’s genetic identity.

Examiner tips

  • Use the term ‘stem cells’ for meristem cells; mention loss of division ability after differentiation.
  • Explain interphase stages (G1 growth, S DNA replication, G2 preparation) before mitosis.
  • State that mitosis gives two identical daughter cells with the same DNA.
  • Keep answer concise and use UK spelling.

Common mistakes

  • Confusing meristem cells with differentiated cells; forgetting that differentiation stops division.
  • Mixing up mitosis with meiosis; not specifying that mitosis gives identical cells.
  • Omitting the interphase stages or the DNA replication step.

Mark scheme (5 marks)

  1. Meristem cells are stem cells / unspecialised cells that retain the ability to differentiate
  2. Once a cell differentiates / becomes specialised it cannot divide to produce an unspecialised cell (or a cell with a different specialised function)
  3. During interphase, DNA is replicated / copied
  4. During interphase, the cell grows and the number of organelles increases
  5. Mitosis produces two daughter cells with identical copies of DNA / identical genetic information

Key terms in this question

meristem · cell cycle

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