Photosynthesis- biology

• Photosynthesis


  Chemical equation: CO₂ + H₂O → CH₂O + O₂
• Unbalanced equation: CO₂ + H₂O → glucose + O₂
• Balanced equation: 6CO₂ + 6H₂O → CH₂O6 + 6O₂
• Photosynthesis


  1. Light

  2. Putting together

  3. Using light
• Leaves


  • Part of the plant which photosynthesises
  • Specialised organs for photosynthesis
• Leaves are green due to chloroplasts and chlorophyll (a green protein)
• Plants produce more carbon dioxide at night because they respire but don't photosynthesize
• Specialised plant cells


  • Cell wall
  • Mitochondria
  • Vacuole
  • Chloroplasts
• Transport tubes


  • Root hair cells
  • Xylem cells
  • Phloem cells
• Phloem transports plant food and xylem transports water and minerals
• Leaf cells


  • Waxy cuticle stops water exiting
  • Upper epidermis protects and prevents water loss
  • Palisade cells for photosynthesis
  • Spongy mesophyll for gas exchange
  • Guard cells regulate transpiration
• Transpiration stream


  The process of water movement through a plant and its evaporation from aerial parts
• Stomata


  • Pores on the underside of leaves that let out CO₂
  • Open during the day to allow gas exchange
  • Close at night to prevent water loss
• Palisade cells


  Cells in plant leaves that contain chloroplasts and are the major site of photosynthesis
• Photosynthesis in plant cells

  1. Make

  2. Sugar for growth, respiration and other life processes
• Chlorophyll


  Found in chloroplasts, enables photosynthesis to occur
• Palisade cells


  • Adapted for photosynthesis as they are towards the top of the leaves and have lots of chloroplasts
• Root hair cells


  Cells on the outside surface of roots that have long tiny hairs that poke into the soil, increasing surface area to absorb more water and minerals
• Root hair cells


  • Hold the plant in place as it grows
  • Absorb water and minerals from the soil
• Root structure


  Roots divide into smaller and smaller branches as they travel into the soil
• Vacuole


  Stores most of the water in root cells
• Mitochondria


  Used to transport minerals in and out of root cells
• Transpiration


  When the plant doesn't absorb all the water from the soil and lets out oxygen through the stomata
• Factors affecting rate of transpiration

  • Temperature - increases
  • Light - increases
  • Humidity - decreases
  • Strong wind - increases