is the set of biological processes that converts absorbed light energy into chemical energy stored in organic compounds.

Context: Definition and significance of photosynthesis

In oxygenic photosynthesis, electrons are stripped from , releasing oxygen (O2) as a byproduct.

Context: Oxygenic photosynthesis and water splitting

Anoxygenic photosynthesis does not produce oxygen because it uses alternative electron donors or strategies that avoid release.

Context: Difference between oxygenic and anoxygenic photosynthesis

Light-dependent reactions generate and , which later power carbon fixation.

Context: Light-dependent reactions and energy carriers

The Calvin cycle is a light-independent sequence that fixes into organic molecules using ATP and NADPH.

Context: Calvin cycle and carbon fixation

Carbon fixation means converting into sugars or carbohydrates.

Context: Meaning of carbon fixation

A synthesizes food directly from CO2 and water using light energy.

Context: Photoautotrophs and carbon sources

A uses organic compounds rather than CO2 as its carbon source for photosynthesis.

Context: Photoheterotrophs and carbon sources

Light energy is absorbed by reaction centers containing photosynthetic pigments/chromophores, which causes in light-dependent reactions.

Context: Cause→effect chain: light absorption to electron transfer

Water splitting in oxygenic photosynthesis releases O2 and provides hydrogen/electrons that causes and formation.

Context: Cause→effect chain: water splitting to NADPH/ATP

ATP and NADPH produced by light-dependent reactions cause CO2 to be fixed into carbohydrates via the cycle.

Context: Cause→effect chain: ATP/NADPH to Calvin cycle carbon fixation

Cyanobacteria produce excess oxygen during oxygenic photosynthesis, which leads to Earth’s oxygenation and enables the evolution of complex life. This effect is driven by contributing oxygen to the Earth.

Context: Cause→effect chain: cyanobacteria oxygen to oxygenation

In the Purple Earth hypothesis, early photosynthesis may have involved archaeal retinal-based systems before the rise of photosynthesis.

Context: Evolutionary history and Purple Earth hypothesis

Photosynthesis is the opposite redox process of cellular respiration: photosynthesis reduces CO2 into carbohydrates, while cellular respiration oxidizes carbohydrates/nutrients to CO2 and water. This contrast is about logic (reduction vs oxidation).

Context: Photosynthesis vs cellular respiration redox logic