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Answer (1)
Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy stored in glucose. This process takes place in the chloroplasts of plant cells, which contain a green pigment called chlorophyll. Chlorophyll absorbs sunlight, and this energy is used to convert carbon dioxide from the air and water from the soil into glucose and oxygen.
The overall chemical equation for photosynthesis can be summarized as:
6 C O 2 + 6 H 2 O + l i g h t e n er g y → C 6 H 12 O 6 + 6 O 2
Here's a step-by-step breakdown of the photosynthesis process:
Light Absorption: Chlorophyll absorbs sunlight, which energizes electrons in a process known as photolysis. This occurs in the thylakoid membranes of the chloroplasts.
Water Splitting: The absorbed energy is used to split water molecules into oxygen, protons, and electrons. Oxygen is released as a byproduct into the atmosphere.
Electron Transport Chain: The energized electrons move through an electron transport chain, which helps pump protons across the thylakoid membrane, creating a proton gradient.
ATP and NADPH Formation: The energy from the proton gradient is used to synthesize ATP (adenosine triphosphate), while electrons reduce NADP+ to NADPH. Both ATP and NADPH are energy carriers used in the next stage of photosynthesis.
Calvin Cycle: This is the second phase of photosynthesis, occurring in the stroma of the chloroplasts. During this cycle, ATP and NADPH produced from the light-dependent reactions are used to convert carbon dioxide into glucose through a series of enzyme-catalyzed reactions.
Understanding photosynthesis is crucial because it is the foundation of life on Earth, providing the energy and organic matter that sustain nearly all organisms.
