Question

Discuss the role of light and pigments in photosynthesis.

Answer 1

Ans.

• Photosynthesis is the process used by the plants for the production of their food by converting light energy into chemical energy.
• During this process, carbohydrates like starch or sugar, are produced from CO2 and water with the help of light in plants.
• Chlorophyll absorbs the energy of sunlight during the process of photosynthesis.
• This absorbed energy from sunlight is then used for the conversion of carbon dioxide and water into sugar molecules while releasing oxygen as a by product.
• Thus, for the process of photosynthesis, light is an important factor as it provides heat energy for the conversion of CO2 and water into sugar molecules and only the plants receiving light energy will survive.
• ATP and NADPH are produced from the energy of sun light.
• NADPH acts as an electron carrier and produce high energy sugar molecules during calvin cycle, which in turn is used by the cells for energy.
• The colorful chemical substances that can reflect a specific wavelength light and absorb other wavelengths are called as pigments.
• Many types of pigments are found in animal skins, flowers and leaves, that impart them some specific colors.
• Pigments play an important role in photosynthesis by helping in the absorption of energy from sunlight.
• At the certain energy level in the chemical structures of these photosynthetic pigments, free electrons revolves at the molecular level.
• Upon the irradiation of light energy on these pigments, electrons jump to the next level of energy by absorbing this energy.
• To come back to their stable energy level, these electrons need to dissipate this absorbed light energy.
• These high energy electrons then either pass their absorbed energy to other molecules or get transfered themselves to the neighbouring molecules.
• Therefore, they release the captured light energy.
• Other molecules then use this released light energy for the synthesis of sugar and other nutrients.
• Thus, we can say that for the process of photosynthesis to take place, presence of sunlight and pigments are of utmost importance.