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# Photosynthesis ## Definition Photosynthesis is the process by which green plants, algae, and some bacteria use sunlight to convert carbon dioxide ($CO_2$) and water ($H_2O$) into glucose ($C_6H_{12}O_6$) and oxygen ($O_2$). It is essential for producing the oxygen we breathe and forms the base of...

# Photosynthesis ## Definition Photosynthesis is the process by which green plants, algae, and some bacteria use sunlight to convert carbon dioxide ($CO_2$) and water ($H_2O$) into glucose ($C_6H_{12}O_6$) and oxygen ($O_2$). It is essential for producing the oxygen we breathe and forms the base of most food chains. ## Equation The balanced chemical equation for photosynthesis is: $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$ ## Stages of Photosynthesis Photosynthesis occurs in two main stages: 1. **Light-Dependent Reactions** (in the thylakoids): * Light energy is absorbed by chlorophyll. * Water molecules split to release oxygen. * Energy is converted into ATP and NADPH. 2. **Calvin Cycle (Light-Independent Reactions)** (in the stroma): * Uses ATP and NADPH to convert $CO_2$ into glucose. * Does not require light but relies on the products of the first stage. ## Adaptations of the Leaf Leaves are specialized for efficient photosynthesis: * **Broad and flat**: Increases light absorption. * **Thin structure**: Shortens the diffusion distance for gases. * **Chloroplasts**: Contain chlorophyll for capturing light energy. * **Stomata**: Regulate gas exchange. * **Veins (Xylem & Phloem)**: Transport water and glucose. ## Limiting Factors Photosynthesis is influenced by: * **Light Intensity**: More light increases photosynthesis up to a point. * **Carbon Dioxide Concentration**: Essential for glucose production. * **Temperature**: Enzymes work best at an optimal temperature. * **Water Availability**: Essential for splitting in light-dependent reactions.