Stem cellsIB MYP Biology: Mind map

Exam questions on Stem cells

1. A developmental biologist in Kyoto is watching a fertilised human egg divide by mitosis. In the first few days the cells in the ball of cells look identical and can still become any type of cell. Later, cells in the same embryo become nerve cells, muscle cells and skin cells, each with a different structure.
   Outline what is meant by differentiation, using one named example.2 marks
2. A horticulturist in Nairobi grows roses to export. To produce thousands of identical, disease-free plants, she cuts tiny pieces of tissue from the tips of growing shoots and roots, places them on nutrient jelly and waits for new plants to grow.
   Explain why the horticulturist takes tissue from the shoot tips rather than from a mature leaf.2 marks
3. A nine-year-old boy in Dubai has leukaemia, a cancer of the white blood cells. Doctors destroy his diseased bone marrow with chemotherapy and then give him a transplant of bone marrow from his healthy sister. Her bone marrow contains adult stem cells.
   Explain how the transplanted bone marrow helps the boy to recover.3 marks