Photosynthesis I

Photosynthesis

A metabolic process by which light energy is captured to reduce CO2 into carbohydrates and oxidize H2O into O2.

Photon

A particle representing a quantum of light or other electromagnetic radiation.

Chlorophyll

A green pigment found in thylakoid membranes that absorbs blue and red light for photosynthesis.

Noncyclic electron transport

An electron transport process that produces NADPH and ATP, involving two photosystems.

Cyclic electron transport

An electron transport process that produces only ATP, with electrons cycling back to photosystem I.

Absorption spectrum

A plot of absorbed light against wavelength for a given pigment.

Action spectrum

A plot of biological activity of an organism as a function of light wavelength.

Calvin cycle

The light-independent reactions of photosynthesis that use ATP, NADPH, and CO2 to produce sugars.

Photophosphorylation

The process of ATP production that is coupled to electron transport in photosynthesis.

Pigments

Molecules that absorb wavelengths in the visible range, allowing for the capture of light energy.

Chlorophyll a

The primary chlorophyll pigment that absorbs light at wavelengths of 680 nm.

Chlorophyll b

A type of chlorophyll that helps capture light energy by absorbing light at higher wavelengths.

Light-dependent reactions

Reactions in photosynthesis that require light; they produce ATP and NADPH.

Electron transport chain

A series of protein complexes that transfer electrons to generate ATP and NADPH in thylakoid membranes.

Accessory pigments

Pigments such as carotenoids that absorb light energy and transfer it to chlorophyll.

Chemiosmosis

The process by which ATP is produced in thylakoid membranes, driven by a proton gradient.