Photosynthesis

• Photosynthesis


  1. Takes place in the leaves

  2. Takes place in chloroplasts

  3. Chlorophyll absorbs light energy

  4. Converts carbon dioxide and water into glucose and oxygen
• Photosynthesis is an endothermic reaction, where energy is transferred from the environment to chloroplasts by light
• Carbon dioxide and water supply for photosynthesis


  1. Carbon dioxide diffuses from the air into leaves through stomata

  2. Water is taken up from soil by roots and transported to leaves via xylem( it diffuses from the soil into the root hair cells by osmosis )
• Products of photosynthesis


  • Glucose is the main product
  • Oxygen is also produced but not as important
• Uses of glucose produced by photosynthesis


  • Cellular respiration, break down the glucose to release energy
  • Making cellulose, strengthening the cell wall
  • converting insoluble starch for storage
  • Making amino acids, for protein synthesis
  • Making oils and fats, for storage
• Plant growth rate is often dependent on the rate of photosynthesis
• Factors affecting the rate of photosynthesis are light intensity, temperature, carbon dioxide concentration, and the amount of chlorophyll
• Carbon dioxide + water ——> (light) glucose + oxygen
• 6CO2+ 6H2O ———> C6H12O6 + 6CO2
• To produce proteins plants also use nitrate ions that are absorbed from the soil
• What makes starch a useful long term storage molecule?

  It is compact 

  It can easily be broken down when needed 

  It is insoluble in water
• Photosynthesis converts light energy from the sun into chemical energy in the chemical bonds of glucose molecules.