For the experiment that, “light is necessary for photosynthesis” the potted plant is
first kept in darkness for two to three days. A leaf from the plant is covered with
black paper strip as shown in the figure. The starch test is done on the leaf after
8 hours of exposure to light.
a) What do you observe when the leaf is tested with iodine solution?
b) Why do you think that the plant was kept in a dark place for 2-3 days
before the activity was carried out?
c) Why is photosynthesis important for us? State any two reasons.
Answers
Answer:
a) The uncovered part of the leaf turns blue-black. This confirms the presence of starch. The covered portion of the leaf remains yellow showing that no starch synthesis occured in this region.
a) The uncovered part of the leaf turns blue-black. This confirms the presence of starch. The covered portion of the leaf remains yellow showing that no starch synthesis occured in this region.b) The black paper strip should be attached tightly on both sides of leaf so that no sunlight enters in covered portion of leaf.
a) The uncovered part of the leaf turns blue-black. This confirms the presence of starch. The covered portion of the leaf remains yellow showing that no starch synthesis occured in this region.b) The black paper strip should be attached tightly on both sides of leaf so that no sunlight enters in covered portion of leaf.c) Photosynthesis is plants taking in water, carbon dioxide, and light to make sugar and oxygen. This is important because all living things need oxygen to survive. All producers make oxygen and sugar for the secondary consumers and then the carnivores eat animals that eat the plants.
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