Which gas is consumed during photosynthesis?

Which gas is consumed during photosynthesis?

• A. Oxygen
• B. Carbon dioxide
• C. Nitrogen
• D. Hydrogen

Answer: (B)

Photosynthesis uses carbon dioxide as the starting material to build sugars. In the chloroplasts, carbon dioxide is fixed through the Calvin cycle, where an enzyme adds CO2 to a five-carbon sugar and eventually forms the triose phosphates that become glucose and other carbohydrates. Water supplies electrons during the light reactions and is split to release oxygen gas as a byproduct, so oxygen is produced, not consumed. Nitrogen and hydrogen gases aren’t directly used as inputs in the main carbon-building steps of photosynthesis. So, carbon dioxide is the gas that is consumed.

Photosynthesis uses carbon dioxide as the starting material to build sugars. In the chloroplasts, carbon dioxide is fixed through the Calvin cycle, where an enzyme adds CO2 to a five-carbon sugar and eventually forms the triose phosphates that become glucose and other carbohydrates. Water supplies electrons during the light reactions and is split to release oxygen gas as a byproduct, so oxygen is produced, not consumed. Nitrogen and hydrogen gases aren’t directly used as inputs in the main carbon-building steps of photosynthesis. So, carbon dioxide is the gas that is consumed.