The diagram shows some transfers of carbon in a small woodland. Carbon dioxide is present in the air, while carbon compounds are found in plants, animals an...
Question 1 Report
The diagram shows some transfers of carbon in a small woodland. Carbon dioxide is present in the air, while carbon compounds are found in plants, animals and dead organisms. A factory beside the woodland burns wood waste for fuel.
(a) Name the processes labelled X and Y. [2]
(b) Describe two routes by which carbon in the tree can become carbon dioxide in the air. [4]
(c) Explain why burning wood waste in the factory increases the concentration of carbon dioxide in the air. [3]
(d) Explain how clearing a large area of woodland could increase atmospheric carbon dioxide concentration in two different ways. [3]
(e) State where aerobic respiration takes place in plant and animal cells. [2]
Answer Details
(a) X is photosynthesis, which transfers carbon dioxide from air into the tree. Y is decomposition, or decay by microorganisms. [2]
(b) Carbon in a tree can become atmospheric carbon dioxide when the tree respires and releases carbon dioxide. It can also pass to a deer when the deer feeds on the tree, followed by deer respiration. Alternatively, the tree can die and decomposers respire as they break it down, releasing carbon dioxide. [4]
(c) Wood contains carbon compounds. Combustion releases this carbon as carbon dioxide, which enters the air faster than it is removed. Atmospheric carbon dioxide concentration therefore increases. [3]
(d) Clearing woodland leaves fewer trees to photosynthesise and remove carbon dioxide. Felled plants may also be burned or decay, and combustion or decomposition releases carbon dioxide. [3]
(e) Aerobic respiration takes place in the mitochondria of both plant and animal cells. [2]
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