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What Are the Products of Light-Dependent Reactions in Photosynthesis?

Everything you eat, whether directly or indirectly, is a product of photosynthesis. For instance, just in one year, photosynthesis produces 160 billion tons of carbohydrates. Photosynthesis is truly a marvelous biological process crucial for life on Earth, as it is responsible not only for food resources but also for the life-sustaining oxygen on the planet. There are two main reaction types in photosynthesis: the light reactions and the Calvin Cycle, or dark reactions. The light-dependent reactions use sunlight, directly, while the Calvin Cycle uses the products of the light reactions to form, among other things, glucose, a prime source of carbohydrates.

Oxygen
- Oxygen is only a byproduct of photosynthesis, but one humans and other oxygen-breathing critters have good reasons to be thankful for. According to Environmental News Network, just algae, microbes and other small water-borne organisms produce around 330 billion pounds of oxygen every year. Oxygen is released when water, H2O, is split into hydrogen and oxygen by harnessing the energy of sunlight.
Electrons
- Although oxygen and edible glucose are the products you are most likely to appreciate from the light-dependent reactions of photosynthesis, it is not the reason plants do it. The most important product of light-dependent reactions for plants is electrons. When plants carry out photolysis, the splitting of water into hydrogen and oxygen, they do it to harvest electrons, just like microscopic solar panels. These electrons are then conducted along a series of electron carriers to fuel the photophosphorylation process of photosynthesis, which converts ADP into ATP, the universal energy currency at the cellular level.
ATP
- ATP stands for adenosine triphosphate. It is the main energy currency in cellular reactions. If you want to get something done in a cell, you will probably need a good reserve of ATP to fuel it. ATP is a direct product of light-dependent reactions, which use the energy released by splitting water into hydrogen and oxygen to generate ATP molecules.
NADPH
- The last step in the light-dependent reactions of photosynthesis is to reduce NADP+, nicotinamide adenine dinucleotide phosphate, one of the main electron carriers in photosynthesis, into NADPH. NADPH, which stands for nicotinamide adenine dinucleotide phosphate-oxidase, is then used to fuel reactions in the Calvin Cycle of photosynthesis.

Nature