Question

What is the source of energy used by plants in photosynthesis?

Answer 1

Hint: Photosynthesis is a process used by plants and other organisms to convert energy into food. Oxygen evolves during this process. The food molecules undergo cellular respiration to produce adenosine triphosphate (ATP), which are used as a fuel to perform metabolic activities of the organism. The organisms that perform photosynthesis to synthesize their own food are called autotrophs.

Complete answer:
The source of energy used by the organisms to do photosynthesis is sunlight. During the process, light energy from the sun is converted into chemical energy. Photosynthesis reaction also requires carbon dioxide and water which enters the plant through stomata and roots respectively.
Photosynthesis reaction is of two types- Light dependent and Light independent. Light dependent reactions occur during the day. First, the chlorophyll in the leaves of the plant absorbs sunlight. The light energy is used to split the water molecule into oxygen and hydrogen ions. The ions go through a series of electron carriers, leading to the accumulation of hydrogen ions. When electrons are transferred from one electron carrier to another, energy is produced (ATP and NADPH). Molecular oxygen is liberated during this process.
In light independent reaction the energy produced during the day is used to transform carbon dioxide into glucose (food).

Note:
Through photosynthesis the plants are able to create their own food. The other organisms which cannot create their food depend on plants for their nutrition. Photosynthesis process is also responsible for the production of oxygen which is needed by almost all organisms for their survival. This process is essential for the sustenance of life on earth. If there is no sunlight, photosynthesis does not occur. Without photosynthesis many living organisms will go extinct.