Plants use a process called photosynthesis to make food. During photosynthesis, plants trap light energy with their leaves. Plants use the energy of the sun to change water and carbon dioxide into a sugar called glucose. Glucose is used by plants for energy and to make other substances like cellulose and starch.

Role of Sunlight in Photosynthesis
Photosynthesis is a crucial process in which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. Sunlight plays a vital role in this process by providing the energy needed to drive the reactions.

Light Absorption
- Sunlight is composed of various wavelengths, including visible light.
- Chlorophyll, the pigment responsible for capturing light energy in plants, absorbs certain wavelengths of light, particularly red and blue light.

Energy Conversion
- When sunlight is absorbed by chlorophyll molecules in the chloroplasts of plant cells, it excites electrons and triggers a series of reactions.
- This energy is used to split water molecules into oxygen and hydrogen ions in a process called photolysis.

ATP and NADPH Production
- The energy from sunlight is also used to convert ADP and inorganic phosphate into ATP, a molecule that stores energy for cellular processes.
- Additionally, NADP+ is reduced to form NADPH, another energy-carrying molecule essential in the Calvin cycle of photosynthesis.

Carbon Fixation
- The ATP and NADPH produced with the help of sunlight are utilized in the Calvin cycle to fix carbon dioxide from the atmosphere into glucose.
- This process involves a series of enzymatic reactions that ultimately produce glucose, the primary product of photosynthesis.
In conclusion, sunlight is indispensable in photosynthesis as it provides the energy necessary to drive the conversion of carbon dioxide and water into glucose and oxygen. Without sunlight, plants would not be able to produce the food they need for growth and survival.