PhotosynthesisIB MYP Biology: Subtopic test

1. 1
   A market gardener near Marrakech in Morocco grows spinach in sunny fields. The dark green spinach leaves make glucose in their cells using light energy, and the gardener wants to understand the process so that she can grow healthier plants.

   (a)

   Which two substances are the reactants in photosynthesis?

   [1 mark]

   • ACarbon dioxide and water
   • BGlucose and oxygen
   • COxygen and water
   • DCarbon dioxide and glucose

   (b)

   In which part of a spinach leaf cell does photosynthesis take place?

   [1 mark]

   • AThe mitochondria
   • BThe nucleus
   • CThe chloroplasts, which contain chlorophyll
   • DThe cell membrane

   (c)

   Write the balanced symbol equation for photosynthesis.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Potato plants grow in cool, humid highland areas of Peru. During the growing season the leaves make large amounts of glucose. By harvest time, the underground tubers of the potato plants are full of stored food, but the leaves contain very little glucose.

   (a)

   Which substance do the potato plants make from glucose and store in their tubers?

   [1 mark]

   • ACellulose
   • BStarch
   • CProtein
   • DChlorophyll

   (b)

   Which substance, made from glucose, strengthens the cell walls of the potato plant?

   [1 mark]

   • AStarch
   • BChlorophyll
   • COxygen
   • DCellulose

   (c)

   Explain why the potato plants convert glucose into starch for storage in the tubers.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A student wants to show that chlorophyll is needed for photosynthesis. She uses a plant with variegated leaves, which have green patches and white patches. She keeps the plant in the dark for 48 hours, then in bright light for six hours. She then tests one leaf for starch with iodine solution. The green patches of the leaf turn blue-black, and the white patches stay orange-brown.

   (a)

   Describe how the student should test the leaf for starch after the six hours in light.

   [3 marks]

   (b)

   Explain the results and evaluate whether the experiment shows that chlorophyll is needed for photosynthesis.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A company in Dubai has built an indoor vertical farm that grows lettuce on stacked shelves under LED lamps. The farm adds carbon dioxide to the air, recycles its water and uses no soil. It produces fresh lettuce all year round in a hot desert climate, but it uses a large amount of electricity.

   (a)

   Explain how the structure of a lettuce leaf is adapted for photosynthesis.

   [6 marks]

   (b)

   Discuss and evaluate the use of indoor vertical farms, like the one in Dubai, to produce food in a hot desert country.

   [6 marks]

   Total for question 4: 12 marks

End of questions