The Process of Photosynthesis
Photosynthesis is a complex process where plants convert sunlight, water, and carbon dioxide into energy-rich glucose, releasing oxygen that sustains life on Earth.
Energy Capture (Light Reaction):
- Photosynthesis begins in the chloroplasts, where chlorophyll absorbs sunlight, which excites electrons in the chlorophyll molecules, giving them energy.
- This energy splits water molecules (H₂O) into oxygen (O₂), protons (H⁺), and electrons (e⁻) in a process called photolysis.
- Oxygen is released into the air, while the electrons and protons are used to create energy molecules called ATP and NADPH.
Carbon Fixation (Dark Reaction/Calvin Cycle):
- In this stage, the plant doesn’t need light directly; it uses the energy stored in ATP and NADPH from the light reaction.
- Carbon dioxide (CO₂) from the air enters the plant through stomata (small openings in leaves).
- An enzyme called RuBisCO combines CO₂ with a molecule called RuBP (Ribulose bisphosphate), creating a series of chemical reactions.
- These reactions produce glucose (C₆H₁₂O₆), which stores chemical energy for the plant.
The plant uses glucose for energy during cellular respiration to grow, repair tissues, and reproduce.
Fun Facts
Here are some interesting facts about photosynthesis:
- Photosynthesis powers 99% of life on Earth.
- Some plants can perform photosynthesis quickly, like algae in oceans, which help produce up to 70% of the world’s oxygen!
- Corn is the world’s fastest photosynthesizing land plant, which grows incredibly quickly!
- Duckweed is the fastest photosynthesizing aquatic plant. Under ideal conditions, it can double its biomass in as little as 24 to 48 hours.
Review
Let’s quickly recap what we learned about photosynthesis:
- Where does photosynthesis occur? Chloroplasts
- What is the main product of photosynthesis? Glucose
- What are the two energy molecules created as part of photosynthesis? ATP & NADPH
- What is the process of splitting water into Oxygen & Hydrogen called? Photolysis
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