During photosynthesis, oxygen gas is released as a byproduct of the light-dependent reactions, which occur in the thylakoid membranes of the chloroplast.
1. Light Energy Absorption: Chlorophyll pigment molecules within the thylakoid membranes absorb photons of light energy from the sun.
2. Electron Excitation: The absorbed light energy excites electrons within the chlorophyll molecules to higher energy levels.
3. Electron Transport Chain: The excited electrons are transferred through a series of protein complexes embedded in the thylakoid membranes. This electron transport chain is known as the photosystem II (PSII) and photosystem I (PSI).
4. Water Splitting: In PSII, the excited electrons are extracted from water molecules, resulting in the release of oxygen gas. This process is called photolysis of water. Two water molecules are split, releasing four electrons, four hydrogen ions (H+), and one molecule of oxygen gas (O2).
2H2O -> 4e- + 4H+ + O2
5. Electron Flow: The released electrons from the water splitting reaction are then transferred through the electron transport chain of PSII and PSI. This flow of electrons produces energy in the form of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), which are essential for the next stage of photosynthesis.
6. Oxygen Release: The oxygen gas released during the water splitting reaction in PSII accumulates and diffuses out of the chloroplast through specialized structures called stomata, located on the surface of leaves. From there, it enters the atmosphere, significantly contributing to the oxygen content.
Overall, the process of photosynthesis allows plants, algae, and some bacteria to capture light energy and convert it into chemical energy in the form of ATP and NADPH, while simultaneously releasing oxygen gas into the environment.
Investigating how oxygen gas is released during photosynthesis
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