Bioenergetics

• Photosynthesis Equation:

  Carbon dioxide + Water -> Glucose + Oxygen
• Photosynthesis balanced equation:

  6CO2 + 6H2O -> C6H12O6 + 6O2
• Factors affecting photosynthesis:

  • Temperature
  • Carbon dioxide concentration
  • Light Intensity
• Light intensity

  • As light increases so does rate of photosynthesis
  • After reaching a certain point any increase in light has no further effect. LIGHT IS NOT THE LIMITING FACTOR
• Carbon dioxide conc:

  • As concentration of CO2 increases so does the rate of photosynthesis
  • After reaching a certain point an increase in CO2 has no effect. CO2 is not a limiting factor
• Temperature:

  • As temperature increases so does the rate of photosynthesis
  • As temperature approaches 45 degrees the rate of photosynthesis drops to zero because the enzymes have been denatured
• Glucose produced in photosynthesis can be used by the plant during respiration to provide energy.
• Glucose can be changed into:

  • Insoluble starch (stored in stem, leaves or roots)
  • Fat or oil (stored in seeds)
  • Cellulose (strengthens cell walls)
  • Proteins (used for growth and for enzymes)

  Plants use nitrate ions to produce proteins from glucose, these are found in the soil
• Photosynthesis is a endothermic reaction.

  Energy needed is supplied by sunlight which is trapped in chlorophyll
• Respiration is exothermic

  It releases energy from glucose for use by body.

  This is needed for:

  • Chemical reactions
  • movement
  • to keep warm
• Aerobic respiration:

  Glucose + Oxygen -> Carbon dioxide + water
• Anaerobic respiration:

  In animals:

  • Glucose -> Lactic acid (+atp)

  In plants and yeast:

  • Glucose -> ethanol + carbon dioxide (+atp)
• Anaerobic respiration in yeast cells is called fermentation