1. Capturing Light Energy:
* Plants contain a green pigment called chlorophyll in organelles called chloroplasts.
* Chlorophyll absorbs light energy, primarily from the red and blue wavelengths of the visible spectrum.
2. Using Water and Carbon Dioxide:
* Plants take in water from the soil through their roots.
* They absorb carbon dioxide from the air through tiny pores on their leaves called stomata.
3. The Light-Dependent Reactions:
* Light energy captured by chlorophyll is used to split water molecules.
* This process releases oxygen as a byproduct, which is released into the atmosphere.
* The light energy is also used to create energy-carrying molecules called ATP and NADPH.
4. The Light-Independent Reactions (Calvin Cycle):
* ATP and NADPH from the light-dependent reactions power the Calvin cycle.
* This cycle uses carbon dioxide from the atmosphere to create glucose (sugar), the plant's primary food source.
5. Storing Food:
* The glucose produced is used by the plant for growth, reproduction, and other metabolic processes.
* Excess glucose is stored as starch in the plant's roots, stems, or leaves.
In Summary:
Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to produce glucose (sugar) as their food source, releasing oxygen as a byproduct. This process is essential for all life on Earth, as it provides the energy and oxygen necessary for the survival of most organisms.
