Photosynthesis: Equation and Process

by Vinodh Reddy


  • Photosynthesis means synthesis of food with the help of sunlight.
  • The overall equation of photosynthesis is
  • Photosynthesis process takes place only in green parts of the plant, mostly in leaves and to lesser extent in green stems or floral parts of the plants.
  • Leaves of the plant are known as light powered food factories.
  • A green substance called chlorophyll in the leaves catches the energy from sunlight, water from soil, CO2 from air and completes the chemical form. This process is called photosynthesis.
  • Chlorophyll pigments are mainly present in cell organelles called plastids (chloroplast).
  • There are different kinds of chlorophyll molecules present in photosynthesis organisms. In plants mostly there are two kinds viz. chlorophyll a and chlorophyll b. Both chlorophyll a and chlorophyll b are very similar in molecular structure, except that the CH3 group in chlorophyll a is replaced by CHO group in chlorophyll b.
  • The CO2 for this process comes from air. It seeps into leaf through tiny holes into lower surfaces known as stomata.
  • Stomata are open during day time and closes during night time.
  • In addition to sugar, This process also produces oxygen which sleeps out in the air.
  • It occurs only in visible light region of wavelength 4000-7500°A. The temperature range is from -35°C to +75°C.
  • It is the only carbon fixing process on earth. The rate is optimum between 10°C to 35°C.
  • Certain bacteria and algae can also capture light energy and use it to make food e.g. photosynthesis bacteria contains chlorophyll in tiny bodies called chromatophores.
  • Essential elements in plants are Carbon – 45%, Oxygen – 3%, Hydrogen – 6%, Nitrogen – 13%.
Photosynthesis equation