Photosynthesis

• Photosynthesis takes place in chloroplasts (subcellular structures in leaves)
• Chloroplasts contain a pigment called chlorophyll that can absorb light
• Light acts as energy used to convert carbon dioxide + water to oxygen + glucose
• These are the equations of photosynthesis

  
• glucose's chemical formula is: C6H12O6
• Photosynthesis is an endothermic reaction
• • Carbon dioxide diffuses into the leaves through the stomata
  • Water is taken up from the soil by the roots and taken up to the leaves by the xylem
• Glucose is used in plants for:

  • Cellular respiration (breaks glucose apart to release energy)
  • Making cellulose (complex carbohydrate used to strengthen cell walls)
  • Making starch (complex carbohydrate for long term storage, as it is compact and insoluble)
  • Making amino acids by combining glucose and nitrate ions (combine amino acids to make proteins)
  • Make oils/fats (stored as future energy source)
• Plants try and keep a good store of starch
• Starch is compact and insoluble, this means unlike glucose it won't let water into the cell via osmosis
• Balanced photosynthesis reaction: 6CO2 + 6H2O ➔ C6H12O6 + 6O2