In oxygenic photosynthesis (as in plants and cyanobacteria), which molecules are the reactants used to produce glucose and oxygen?

• A. Carbon dioxide and oxygen
• B. Carbon dioxide and water
• C. Nitrogen gas and water
• D. Glucose and oxygen

Answer: (B)

Verified step by step guidance

1. Understand the overall chemical equation for oxygenic photosynthesis, which converts light energy into chemical energy stored in glucose.
2. Recall that the general equation for oxygenic photosynthesis is: \$6\ \text{CO}_2 + 6\ \text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\ \text{O}_2$.
3. Identify the reactants on the left side of the equation: carbon dioxide (\(\text{CO}_2\)) and water (\(\text{H}_2\text{O}\)).
4. Recognize that glucose (\(\text{C}_6\text{H}_{12}\text{O}_6\)) and oxygen (\(\text{O}_2\)) are the products formed during the process.
5. Conclude that the molecules used as reactants in oxygenic photosynthesis to produce glucose and oxygen are carbon dioxide and water.