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B2.3.2—Properties of stem cells

Stem cells are unspecialized cells that self-renew by division and retain potency to form specialized cells for growth, repair, and therapy.

Syllabus
First assessment 2025
Objective
B2.3.2
Level
HL

Exam analysis

Chance of appearing5%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper1
Typical marks1

Common command terms

  • State
  • Identify
  • Describe
  • Outline

Scoring notes

Common mistake
Calling stem cells already specialized rather than undifferentiated.

Recent exam appearances

November 2025Paper1A ["HL"] · TZ314[ 1 ]B2.3.2—Properties of stem cells
May 2022Paper2 ["HL"] · TZ17(a)[ 3 ]B2.3.2—Properties of stem cells
November 2019Paper1 ["HL"] · TZ01[ 1 ]B2.3.2—Properties of stem cells
May 2018Paper1 ["HL"] · TZ21[ 1 ]B2.3.2—Properties of stem cells
November 2016Paper1 ["HL"] · TZ02[ 1 ]B2.3.2—Properties of stem cells
Practice this objective

Coverage 2014–2025 · Updated 15 Jul 2026

Differentiation and stem-cell potential

Differentiation is the process in which cells with the same genome activate different sets of genes, make different proteins, and become specialised for particular functions.

A developing embryo can use morphogen concentration gradients as positional information: different concentrations activate different gene-regulatory pathways and produce different cell fates.

Causal chain: same genome → signal or morphogen concentration → selective gene activation → different proteins → specialised cell structure and function. Stem cells self-renew by mitosis and retain the capacity to differentiate along more than one pathway.

Differentiation changes gene expression, not the chromosome set. Self-renewal is the ability to keep dividing; potency is the range of specialised cell types a stem cell can produce.

Properties of stem cells

Assessment in practice

1–2 marks
How it is assessed

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

Command terms

State / Identify / Describe / Outline

What earns marks

Build the answer around this relationship: Stem cells can divide while remaining undifferentiated.

Watch for

Calling stem cells already specialized rather than undifferentiated.

Representative question

Question 1

[Maximum number: 5]

Describe the characteristics of stem cells that make them potentially useful in medicine.

Cell Specialization and Size Limits

Cell specialization comes from differential gene expression after a zygote divides, stem cells provide self-renewing cells with different potencies, and cell size is constrained by surface area-to-volume ratio because exchange depends on surface area while demand depends on volume.

  • Differentiation: same genome, different active genes, different proteins.
  • Stem cells: self-renewal plus potency; specify totipotent, pluripotent, or multipotent when needed.
  • SA:V: as cells grow, exchange becomes less efficient because volume increases faster than surface area.

Concept essentials

  • Stem cells can divide while remaining undifferentiated.
  • Stem cells can differentiate into specialized cell types.
  • Therapeutic value comes from repair, replacement, research, and disease treatment potential.
  • Embryonic stem cells usually have broader developmental potential than most adult stem cells.