Bioenergetics

• Photosynthesis


  The process by which plants make glucose from sunlight
• Endothermic reaction


  A reaction in which energy is transferred from the environment to the chloroplasts by light
• Photosynthetic reaction


  Carbon dioxide + water → glucose + oxygen
• Carbon dioxide


  CO2
• Water


  H2O
• Oxygen


  O2
• Glucose


  C6H12O6
• The rate of photosynthesis is affected by a number of factors
• Temperature


  • With an increase in temperature, the rate of photosynthesis increases until enzymes begin to denature
• Light intensity


  • The higher the light intensity, the faster the rate of photosynthesis
• Carbon dioxide concentration


  • As the concentration of carbon dioxide increases, the rate of photosynthesis increases
• Amount of chlorophyll


  • Chlorophyll is essential for converting light energy to food for the plant
• Measuring oxygen production to calculate rate of photosynthesis


  Pondweed in test tube, capillary tube, syringe, lamp, water bath, measure distance bubble moves
• Limiting factor


  An environmental condition that, in low levels, restricts any increase in the rate of photosynthesis
• Graphs showing limiting factors

  • One line leveling off, two lines, three lines
• Farmers can use knowledge of limiting factors to enhance conditions in the greenhouse for greater rate of photosynthesis
• Inverse proportion


  As the distance between the light source and the plant increases, the light intensity decreases
• Inverse square law


  Light intensity is inversely proportional to the square of the distance
• Uses of glucose from photosynthesis

  • For respiration
  • Converted into starch for storage
  • To produce fat or oil for storage
  • To produce cellulose to strengthen cell walls
  • Combined with nitrates to form amino acids and proteins
• Respiration


  The process of transferring energy from glucose so living processes can occur
• Exothermic


  Energy is transferred to the environment
• Aerobic respiration


  Respiration that uses oxygen and yields the most energy
• Anaerobic respiration


  Respiration that occurs without oxygen and does not yield as much energy
• Aerobic respiration


  Glucose + oxygen → carbon dioxide + water
• Anaerobic respiration in animals

  Glucose → lactic acid
• Anaerobic respiration in plants and yeast

  Glucose → ethanol + carbon dioxide
• Oxygen debt


  The amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells
• Metabolism


  The sum of all the reactions in a cell or the body, controlled by enzymes
• Metabolic reactions


  • Glucose to starch, glycogen, cellulose
  • Glycerol and fatty acids to lipids
  • Glucose and nitrate to amino acids and proteins
  • Respiration reactions
  • Urea forming from protein breakdown