ZIMSEC O Level Combined Science: Photosynthesis

  • Green plants are the food and oxygen producers of the living world.
  • They manufacture organic molecules from inorganic raw materials.
  • Animals rely on green plants to make food that provides them with energy and oxygen.
  • Green plants are thus known as producers and animals are in turn known as consumers.
  • Only green plants can make food.
  • The process by which green plants make food from inorganic materials is known as photosynthesis.
  • Photosynthesis- is the process by which green plants use light energy to combine carbon dioxide and water into carbohydrates and releasing oxygen as a by product.
  • The word equation for photosynthesis is:
  • \text{Carbon Dioxide+Water}\xrightarrow[light]{chlorophyll}\text{Carbohydrates+Oxygen}
  • There are two types of carbohydrates made during the process of photosynthesis:
  • sugars and starch.
  • Testing for either of these molecules in plants will show whether plants are making food.
  • Most plants produce although others like cereals (e.g. maize) produce sugars first.
  • The simple sugar compound (glucose) is converted into starch for storage in the leaves.
  • Chlorophyll is the green pigment found in plants.
  • It is commonly found in plant leaves.
  • It absorbs light energy from the sun and converts it into chemical energy.
  • It absorbs light energy from the usn which can then be used to manufacture food.

To access more topics go to the Combined Science Notes page.


Quick NetOne, Econet, And Telecel Airtime Recharge