Photosynthesis

• Where does photosynthesis happen ?

  • In chloroplasts
• what is the word equation for photosynthesis?

  carbon dioxide + water ——-> glucose +oxygen

  light
• what is the symbol equation for photosynthesis ?

  • 6CO2 + 6H2O ——-> C6H12O6 + 6O2
• What type of reaction is photosynthesis ?

  • Endothermic
• What is an endothermic reaction ?

  • Energy is taken in during the reaction
• What factors affect the rate of photosynthesis ?

  • Light intensity , concentration of CO2 and temperature
• what are photosynthetic organisms, what do they do ?

  • Green plants and algae
  • use energy from the sun to make glucose
• What is some of the glucose used for ?

  • Making larger , complex molecules that the plants or algae need to grow
• What is an organisms biomass ?

  • The mass of living material
• How does light intensity affect the rate of photosynthesis?

  Increased light intensity generally increases the rate of photosynthesis up to a certain point.
• What materials are used in the practical to measure the rate of photosynthesis?

  • Empty gas syringe
  • Sodium hydrogencarbonate (to provide CO2)
  • Source of white light
  • Pondweed
• What is the purpose of adding sodium hydrogencarbonate to the water in the experiment?

  To ensure the plant has enough CO2 for photosynthesis.
• What is the role of the white light source in the experiment?

  The white light source provides the light energy necessary for photosynthesis.
• What is the procedure for measuring the rate of photosynthesis using pondweed?

  Pondweed is left to photosynthesize for a set amount of time while oxygen is collected in a gas syringe.
• How is the volume of oxygen produced measured in the experiment?

  Oxygen released during photosynthesis collects in the gas syringe, allowing for accurate volume measurement.
• How can the rate of oxygen production be calculated?

  Rate of oxygen production = volume produced / time taken.
• What control variables should be maintained in the experiment?

  • Temperature
  • CO2 concentration
• what is the inverse square law ?

  Light intensity proportional to 1/distance squared