Photosynthesis as an energy transfer process

Need to know

What you need to know

• Photosynthesis is the process of converting light energy into chemical energy stored in organic molecules like glucose.
• The overall balanced equation is 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂.
• Photosynthesis occurs in chloroplasts. The light-dependent reactions are in the thylakoid membranes, and the light-independent reactions are in the stroma.
• Photosynthetic pigments (chlorophylls, carotenoids) absorb light energy. An absorption spectrum shows which wavelengths are absorbed, while an action spectrum shows the rate of photosynthesis at those wavelengths.
• The light-dependent stage uses light to produce ATP and reduced NADP through photophosphorylation and involves the photolysis of water.
• The light-independent stage (Calvin cycle) uses ATP and reduced NADP to fix CO₂ into triose phosphate, which is then used to make glucose and regenerate RuBP.
• Photosynthesis is fundamental to life as it forms the base of food webs and produces the atmospheric oxygen required for aerobic respiration.

Explanation

Photosynthesis as an energy transfer process

1. Photosynthesis is the process of converting light energy into chemical energy stored in organic molecules like glucose.
2. The overall balanced equation is 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂.
3. Photosynthesis occurs in chloroplasts. The light-dependent reactions are in the thylakoid membranes, and the light-independent reactions are in the stroma.
4. Photosynthetic pigments (chlorophylls, carotenoids) absorb light energy. An absorption spectrum shows which wavelengths are absorbed, while an action spectrum shows the rate of photosynthesis at those wavelengths.