Step 1: Understanding the Concept:
Autotrophic organisms, such as green plants, need to synthesize their own organic food using energy acquired from their external environment.
Step 2: Key Formula or Approach:
The approach is to analyze the metabolic pathways in plants and identify the one responsible for capturing sunlight to form glucose.
The overall reaction is \( 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \).
Step 3: Detailed Explanation:
Photosynthesis is the fundamental biological process by which green plants, algae, and some bacteria convert light energy into chemical energy.
During this process, carbon dioxide and water are transformed into glucose and oxygen in the presence of sunlight and the green pigment chlorophyll.
Respiration is the cellular process of breaking down food molecules to release energy for cellular work, which is the opposite of synthesizing food.
Transpiration is the process of water vapor loss from plant leaves through the stomata.
Fermentation is an anaerobic metabolic pathway used to break down glucose without the presence of oxygen.
Step 4: Final Answer:
Plants use the process of photosynthesis to convert light energy into chemical energy.