photosynthesis

• Photosynthesis


  The process that allows plants to grow and survive
• Photosynthesis


  1. Takes place in the leaves

  2. Occurs in chloroplasts

  3. Chlorophyll absorbs light energy

  4. Converts carbon dioxide and water into glucose and oxygen
• Factors affecting photosynthesis


  • Light intensity
  • Temperature
  • Concentration of carbon dioxide in the air
  • Amount of chlorophyll in plants
• The chemical equation for photosynthesis is: 6CO2 + 6H2O → C6H12O6 + 6O2
• Chlorophyll


  Pigment within chloroplasts that absorbs the light energy needed for photosynthesis
• Endothermic reaction


  A reaction where energy is transferred from the environment to the reactants
• Plants have less chlorophyll


  They won't be able to carry out as much photosynthesis
• How plants get reactants for photosynthesis

  1. Carbon dioxide diffuses into leaves through stomata

  2. Water is taken up from soil by roots and transported to leaves via xylem
• Different plants naturally have different amounts of chlorophyll
• The level of chlorophyll within an individual plant can vary due to disease, environmental stress, or lack of nutrients like water
• Glucose


  The main product of photosynthesis that plants use
• Factors normally referred to as limiting factors for photosynthesis are light, carbon dioxide, and temperature
• Uses of glucose by plants

  • Cellular respiration
  • Making cellulose
  • Making starch
  • Making amino acids
  • Making oils and fats
• Graphing factors affecting photosynthesis

  1. Plot light intensity on x-axis, rate of photosynthesis on y-axis

  2. As light intensity increases, rate of photosynthesis increases up to a point where it plateaus

  3. Plateauing means another factor is limiting, such as carbon dioxide or temperature
• Plant growth rate is often dependent on the rate of photosynthesis
• Graphing carbon dioxide effect on photosynthesis

  Rate of photosynthesis increases with carbon dioxide concentration up to a plateau
• Factors that affect the rate of photosynthesis are light intensity, temperature, carbon dioxide concentration, and amount of chlorophyll
• Graphing temperature effect on photosynthesis

  Rate increases initially as enzymes work faster, then decreases as enzymes denature above 45 degrees
• Graphs may show multiple limiting factors, e.g. light intensity at different temperatures or carbon dioxide concentrations
• Farmers use greenhouses, artificial lighting, carbon dioxide injection, and heaters to create optimal conditions for photosynthesis
• Farmers also use fertilizers and pesticides to support plant growth
• Creating optimal conditions for photosynthesis can be costly for farmers