In plants, algae, and cyanobacteria, what is the main purpose of photosynthesis?

• A. To break down glucose to produce ATP through cellular respiration
• B. To absorb minerals from the soil and transport them to leaves
• C. To convert oxygen into carbon dioxide for use in metabolism
• D. To convert light energy into chemical energy stored in sugars (e.g., glucose)

Answer: (D)

Verified step by step guidance

1. Understand that photosynthesis is a process used by plants, algae, and cyanobacteria to capture energy from sunlight.
2. Recognize that the main goal of photosynthesis is to convert light energy into chemical energy, which is stored in the bonds of sugar molecules like glucose.
3. Recall the general photosynthesis equation: \$6\,CO_2 + 6\,H_2O + light \ energy \rightarrow C_6H_{12}O_6 + 6\,O_2$, which shows carbon dioxide and water being converted into glucose and oxygen using light energy.
4. Note that photosynthesis produces glucose, which can later be used by the organism for energy through cellular respiration, but photosynthesis itself is about energy capture and storage, not energy release.
5. Conclude that the main purpose of photosynthesis is to transform light energy into chemical energy stored in sugars, enabling the organism to fuel its metabolic activities.