Sure, let's break down the process of photosynthesis to identify what combines with carbon dioxide to make sugar and oxygen.
### Photosynthesis Overview
Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy stored in glucose (sugar). This process can be summarized by the following chemical equation:
[tex]\[
6 \text{CO}_2 + 6 \text{H}_2 \text{O} \rightarrow \text{C}_6 \text{H}_{12} \text{O}_6 + 6 \text{O}_2
\][/tex]
### Analyzing the Chemical Equation
1. Reactants (on the left side of the equation):
- Carbon Dioxide ([tex]\(\text{CO}_2\)[/tex]): 6 molecules
- Water ([tex]\(\text{H}_2 \text{O}\)[/tex]): 6 molecules
2. Products (on the right side of the equation):
- Glucose ([tex]\(\text{C}_6 \text{H}_{12} \text{O}_6\)[/tex]): 1 molecule
- Oxygen ([tex]\(\text{O}_2\)[/tex]): 6 molecules
### Key Steps in Photosynthesis
- Light Reactions: These occur in the thylakoid membranes of chloroplasts where light energy is absorbed by chlorophyll and converted to chemical energy in the form of ATP and NADPH. Water ([tex]\(\text{H}_2 \text{O}\)[/tex]) is split during these reactions, releasing oxygen ([tex]\(\text{O}_2\)[/tex]).
- Calvin Cycle (Dark Reactions): These occur in the stroma of the chloroplasts where ATP and NADPH produced in the light reactions are used to convert carbon dioxide ([tex]\(\text{CO}_2\)[/tex]) into glucose ([tex]\(\text{C}_6 \text{H}_{12} \text{O}_6\)[/tex]).
### Identifying the Combining Molecule
In the process described by the given chemical reaction:
[tex]\[
6 \text{CO}_2 + 6 \text{H}_2 \text{O} \rightarrow \text{C}_6 \text{H}_{12} \text{O}_6 + 6 \text{O}_2
\][/tex]
We see that carbon dioxide ([tex]\(\text{CO}_2\)[/tex]) combines with:
- Water ([tex]\(\text{H}_2 \text{O}\)[/tex])
The molecule that combines with carbon dioxide to make sugar (glucose) and oxygen during photosynthesis is water (H₂O).
### Conclusion
Based on the analysis of the photosynthesis process and the given chemical equation, the correct answer to the question "During photosynthesis, what combines with carbon dioxide to make sugar and oxygen?" is:
H₂O (water).
