Bioenergetics

• Photosynthesis


  The reaction that plants use to trap light energy
• Plants use light for their source of energy
• Photosynthesis


  • It is an endothermic reaction
  • It takes place in the leaves of a plant
  • Leaves contain the green chemical chlorophyll
• Photosynthesis


  1. Plant takes in carbon dioxide and water

  2. Light energy is absorbed by chlorophyll

  3. Light energy is used to convert carbon dioxide and water into glucose

  4. Oxygen is also produced
• Chemical formulas


  • Carbon dioxide (CO2)
  • Water (H2O)
  • Glucose (C6H12O6)
  • Oxygen (O2)
• Light intensity increases


  Rate of photosynthesis increases
• Limiting factor


  The factor that is in short supply and is limiting the rate of photosynthesis
• Carbon dioxide level increases

  Rate of photosynthesis increases
• Factors affecting rate of photosynthesis

  • Light intensity
  • Carbon dioxide level
  • Amount of chlorophyll
  • Temperature
• As temperature increases, enzymes involved in photosynthesis work faster, but if temperature keeps increasing, enzymes will denature and rate of photosynthesis will fall
• Photosynthesis

  Carbon dioxide + water + light energy → Glucose + Oxygen
• Respiration

  Process that releases energy from glucose in the mitochondria
• Photosynthesis only produces glucose during the day

  Plant cells respire all the time, including at night
• Starch

  Insoluble storage molecule produced from glucose, can be converted back to glucose when needed
• Fats and oils

  Storage form of energy produced from glucose in many plants
• Cellulose

  Molecule in plant cell walls, made from glucose produced by photosynthesis
• Amino acids

  Produced from glucose, used by plants to synthesize proteins
• Peas are a good protein source
• Plants need to absorb nitrate ions from the soil to make amino acids from glucose