Leaves Prepare Starch by the Process of Photosynthesis

Our Objective:

Show that starch is prepared during the process of photosynthesis.

The Theory:

Photosynthesis is the process through which green plants (mainly) transform solar energy into chemical energy that can be used. Plants need the energy to grow, reproduce, and defend themselves. Excess energy from photosynthesis is stored as starch in plant tissue. Starch is a powdery white material. It stores glucose, which plants use as a source of nutrition. Photosynthesis is confirmed by the presence of starch in a leaf because photosynthesis is required for starch production.

The chemical equation can be represented as 6CO2+6H2O → C6H12O6+6O2

The plant uses glucose as an immediate product of photosynthesis, and any excess glucose is stored as starch in the leaves. Because glucose is used up, it is no longer detectable. However, because starch is retained in plants and can be easily detected, it is frequently employed as a measure of photosynthesis in leaves.

From our experiment, Chlorophyll is destroyed by alcohol, and leaves are killed by hot water. The leaf is no longer green as a result. One of the leaves changes to a blue-black colour after exposure to iodine because starch is present and iodine serves as an indication—the other leaf changes from green to reddish-brown.

The leaf exposed to light changes colour from green to blue-black, suggesting that it has been undergoing photosynthesis and making starch.

Types of photosynthesis:

The two forms of photosynthesis are as follows:

  • Oxygenic photosynthesis
  • Anoxygenic photosynthesis

Oxygenic photosynthesis:

Plants, algae, and cyanobacteria are more likely to use oxygenic photosynthesis. To create energy, light energy transfers electrons from water to carbon dioxide throughout this process. Carbon dioxide is reduced, water is oxidised, and oxygen is produced along with carbohydrates during this transfer of electrons.

Plants absorb carbon dioxide and release oxygen into the atmosphere during this process.

Chemical Equation is as follows:

6CO2+ 12H2O + LIGHT ENERGY → C6H12O6 + 6O2 + 6H2O

Anoxygenic photosynthesis:

Purple and green sulphur bacteria, found in various aquatic settings, are two examples of bacteria that often engage in this sort of photosynthesis. During the procedure, oxygen is not created.

CO2 + 2H2A + LIGHT ENERGY → [CH2O] + 2A + H2O

Factors affecting the Photosynthesis process:

The process of photosynthesis is influenced/affected by several things. Which are:

  • Light Intensity: The rate of photosynthesis will increase as the light increases. The rate of photosynthesis will also be lower under low light conditions.
  • The CO2 Concentration: A plant's photosynthesis is accelerated by a greater CO2 concentration. 300 to 400 PPM of CO2 are necessary.
  • Temperature: Photosynthesis is most efficient when the temperature is between 25 and 35 degrees Celsius.
  • Water: Stomatal opening necessitates a vital amount of water, which is also a crucial step in photosynthesis.
  • Pollution: As the amount of polluting particles in the environment rises, they clog the somatic cells' pores, making it challenging to absorb carbon dioxide.

The significance of photosynthesis:

The photosynthesis process is crucial for the continuation of the food chain and the survival of living things. Additionally, it generates oxygen, which is necessary for breathing.

Learning Outcomes:

  1. Students will learn and practice basic laboratory skills.
  2. They will learn how to extract chlorophyll from a leaf.
  3. Learn about the indicator that can be used to identify starch.
  4. Students will have useful information about the photosynthesis process.