Specialised cellsIB MYP Biology: Mind map

Exam questions on Specialised cells

1. A haematologist examines a drop of blood under a microscope. She sees a very large number of small, round cells with a dip in the middle and no nucleus, and a few larger cells that have a lobed nucleus and an irregular outline.
   Explain how two features of red blood cells help them to carry oxygen.2 marks
2. A botanist studies the cells of a young plant. She identifies palisade cells near the top surface of a leaf, root hair cells on the surface of a root, and xylem vessels carrying water up the stem.
   Explain how the structure of a palisade cell helps it to carry out photosynthesis.2 marks
3. A student wants to find out whether root hair cells help a plant to absorb water. She sets up two cress seedlings of the same species in identical test tubes of water, with a thin layer of oil on top of the water to stop evaporation. She cuts the bottom 1 cm off the roots of one seedling, which removes its root hairs, and leaves the roots of the other seedling whole. She leaves both for 24 hours.
   State a testable hypothesis for the investigation, with a scientific reason, and identify the independent variable.3 marks