Light-Dependent Reactions

Flashcards covering key terms and concepts related to the light-dependent reactions of photosynthesis.

Light-dependent reactions

The initial phase of photosynthesis that converts solar energy into chemical energy in the form of ATP and NADPH.

Chlorophyll

The main photosynthetic pigment found in plants that absorbs light energy, particularly in the blue and red wavelengths.

Photon

A particle of light that carries energy proportional to its frequency.

Photosystem II (PS II)

The photosystem that absorbs light at 680 nm and is involved in water splitting.

Photosystem I (PS I)

The photosystem that absorbs light at 700 nm and ultimately helps in the reduction of NADP+ to NADPH.

Electron transport chain (ETC)

A series of protein complexes in the thylakoid membrane that transfer electrons and pump protons, creating a proton gradient.

Chemiosmosis

The process where protons flow back into the stroma through ATP synthase to produce ATP.

NADPH

A reduced coenzyme that carries electrons and is used in the Calvin cycle.

Noncyclic photophosphorylation

The process where light energy generates ATP and NADPH without the recycling of electrons.

Cyclic photophosphorylation

A process that generates ATP only, without reducing NADP+ or splitting water.

Action spectrum

A graph that shows the effectiveness of different wavelengths of light in driving photosynthesis.

Stroma

The fluid-filled space surrounding the thylakoids in chloroplasts where the Calvin cycle takes place.

Photophosphorylation

The addition of a phosphate group to ADP to form ATP using light energy.

Light harvesting complex

A collection of pigments that capture light energy and funnel it to the reaction center.

Primary electron acceptor

The molecule that accepts excited electrons from the reaction center of a photosystem.