absorption of visible light

Definition

Target type: biologicalprocess

The reception of a (visible light) photon by a cell, visible light being defined as having a wavelength within the range 380-780 nm. [GOC:go_curators, ISBN:0198506732]

Visible light absorption is a fundamental process in biology, particularly in photosynthesis. When light strikes a molecule, the energy from the light can be absorbed by electrons within the molecule, causing them to move to a higher energy level. This transition from a lower to higher energy level is known as excitation. In photosynthetic organisms, the light-absorbing molecules are pigments, such as chlorophyll. Chlorophyll absorbs light primarily in the blue and red wavelengths of the visible spectrum, reflecting green light, which is why plants appear green. When chlorophyll absorbs light, its electrons are excited to a higher energy level. This energy is then used to power the chemical reactions of photosynthesis, converting carbon dioxide and water into glucose and oxygen. The process begins with the capture of light energy by chlorophyll, which is embedded within specialized protein complexes in the thylakoid membranes of chloroplasts. The absorbed light energy excites electrons in the chlorophyll molecule, causing them to jump to a higher energy level. These high-energy electrons are then passed along an electron transport chain, releasing energy that is used to pump protons across the thylakoid membrane, generating a proton gradient. The proton gradient is then used to drive the synthesis of ATP, an energy-rich molecule. The excited electrons from chlorophyll are eventually used to reduce NADP+ to NADPH, another important energy carrier. The energy stored in ATP and NADPH is then used to fix carbon dioxide into sugars during the Calvin cycle, the final stage of photosynthesis.'
"

Proteins (1)

Compounds (2)