PhotosynthesisIB MYP Sciences: Mind map

Exam questions on Photosynthesis

1. A greenhouse grower in the Netherlands grows tomato plants. The leaves make glucose from carbon dioxide and water using energy from light, in a process that also releases a gas into the greenhouse air.
   State the role of chlorophyll in photosynthesis.2 marks
2. Photosynthesis can be summarised by an incomplete symbol equation in which two of the numbers have been left out: ? CO₂ + 6 H₂O → C₆H₁₂O₆ + ? O₂. The glucose produced is used by the plant in several ways.
   State two ways in which a plant uses the glucose made in photosynthesis.2 marks
3. A student wants to find out whether light is needed for photosynthesis. She keeps a geranium plant in a dark cupboard for 24 hours. She then covers one leaf completely with aluminium foil and places the plant in bright light for two days. She removes the covered leaf and an uncovered leaf and tests both for starch. She boils each leaf in water, heats it in hot ethanol, rinses it and adds iodine solution. The uncovered leaf turns blue-black. The covered leaf stays orange-brown.
   Describe the purpose of each of the following steps in the starch test: boiling the leaf in water, heating the leaf in hot ethanol, and adding iodine solution.3 marks