Biology HL

1. 1.

   Compare a pluripotent embryonic stem cell with a multipotent bone-marrow stem cell. Explain how stem-cell niches support tissue renewal and why a differentiated cell can differ in function from another cell with essentially the same genome.

   [4 marks] · no calculator
2. 2.

   Type I pneumocytes are extremely thin; type II pneumocytes contain many secretory vesicles that release surfactant. Explain the contribution of each type to alveolar function and why having two specialized cell types can be advantageous.

   [4 marks] · no calculator
3. 3.

   A skeletal muscle fibre is long and contains many nuclei; a cardiac muscle cell is shorter and branched. Both contain contractile myofibrils. Explain how these observations relate to specialization and why the skeletal fibre challenges an overly simple claim that every animal cell is small with one nucleus.

   [4 marks] · no calculator
4. 4.

   A hypothetical tissue stem cell divides, producing a daughter that remains a stem cell and a daughter that differentiates. Explain how this can support long-term tissue renewal and why multipotency does not mean the cell can form every body-cell type.

   [3 marks] · no calculator
5. 5.

   Explain how type I and type II pneumocytes contribute differently to gas exchange in mammalian alveoli. Predict a consequence of reduced surfactant secretion without claiming that type II cells normally provide the thinnest gas-diffusion surface.

   [3 marks] · no calculator

Original, unofficial practice questions from SubjectScout — not official past-paper questions or complete syllabus coverage. Added English teaching explanations are AI-authored; independent teacher review is pending.