Question

Indicate whether the following statements are true or false. If a statement is false, explain why it is false.

A. Photosynthetic organisms release only O2 into the atmosphere, while nonphotosynthetic organisms release only CO2.
B. The cycling of carbon through the biosphere first requires the incorporation of inorganic CO2 into organic molecules.
C. The oxidation of one molecule is always coupled to the reduction of a second molecule.
D. During cellular respiration, carbon-containing molecules become successively more oxidized until they reach their most oxidized form, as CO2.

Answer 1

Photosynthetic organisms release O2 and convert CO2 into organic compounds, not release only CO2. The cycling of carbon begins with the incorporation of CO2 into organic molecules. The oxidation of one molecule is always coupled with the reduction of another molecule. Carbon-containing molecules become more oxidized during cellular respiration until they reach their most oxidized form, CO2.

Step-by-step explanation:

A. False. Photosynthetic organisms not only release O2 but also consume CO2 during the process of carbon fixation. They convert CO2 into organic compounds, such as glucose, while releasing oxygen as a byproduct.

B. True. The cycling of carbon through the biosphere starts with the incorporation of inorganic CO2 into organic molecules through photosynthesis.

C. True. The oxidation of one molecule is always coupled with the reduction of another molecule, following the principle of conservation of energy.

D. True. During cellular respiration, carbon-containing molecules become progressively more oxidized, releasing energy and resulting in the production of CO2 as the most oxidized form of carbon.