Photosynthesis

• Photosynthesis is the process by which organisms convert light energy into chemical energy
• A network of xylem vessels brings water to the leaves and phloem carries away sugars produced in photosynthesis
• The arrangement of leaves minimises overlapping so leaves aren't casting shadows over each other
• There are lots of stomata which open and close in response to changes in light intensity
• There is a transparent cuticle and epidermis that allows light through
• Leaves have a large surface area to collect as much solar energy as possible
• There are many air spaces in the lower mesophyll layer to allow the diffusion of oxygen and carbon dioxide
• Long narrow upper mesophyll cells are packed with chloroplasts
• Chloroplast is found in the thylakoid membrane
• Light is absorbed by chlorophyll
• Light-dependent reaction

  • an "electron flow" is created and causes the photolysis of water
  • produces reduced NADP, ATP and oxygen
• Light-independent reaction

  • protons are used to reduce carbon dioxide to produce sugars and other organic molecules