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IB Biology SL 2.3.3 Stem-Cell Release Evidence Question Bank

Practise IB Biology SL 2.3.3 using the exact SL evidence on drug-response controls, stem-cell release and CXCL12 mRNA production.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Compare drug treatments with a control using stem-cell release and CXCL12 mRNA evidence.
  • Relate CXCL12 gene expression to regulated release of stem cells from adult tissue.
  • Interpret treatment-response data to distinguish changes in stem-cell release from molecular evidence.

B2.3.3—Stem cell niches in adult humans question 1

[Maximum number: 3]

Stem cells in the bone marrow can be forced into blood vessels in a process called mobilization. Mobilization of stem cells from the bone marrow into the blood vessels represents the basis for modern bone marrow transplantation procedures.

To test the effect of light on the mobilization of stem cells, mice were subjected to a simulated "jet lag" by advancing the light-dark cycle by 12 hours. This was done by subjecting mice to a 24 -hour light period before the results shown in the graph were recorded. The results were compared to the stem cells in control mice under normal conditions of 12 hours of light ( □ ) and 12 hours of darkness ( dark box) and 12 hours of darkness ( dark box ).

Figure for Question B2.3.3—Stem cell niches in adult humans question 1 — IB Biology SL
Figure for Question B2.3.3—Stem cell niches in adult humans question 1 — IB Biology SL

Compare the effect of isoprenaline and clenbuterol with the normal release of stem cells and the production of mRNA for CXCL12.

Figure for Question B2.3.3—Stem cell niches in adult humans question 1 — IB Biology SL
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