The Process of Photosynthesis

Vocabulary flashcards covering the key terms, structures, and steps of the light-dependent and light-independent reactions in photosynthesis.

Light-Dependent Reactions

A primary set of photosynthetic reactions occurring in the thylakoids that use light energy and water to produce $ATP$, $NADPH$, and oxygen gas ($O_2$).

Light-Independent Reactions

A primary set of photosynthetic reactions occurring in the stroma where $ATP$ and $NADPH$ are used to synthesize high-energy sugars from carbon dioxide ($CO_2$).

Thylakoids

Saclike photosynthetic membranes inside chloroplasts that contain clusters of chlorophyll and proteins called photosystems.

Photosystems

Clusters of chlorophyll and proteins located in thylakoid membranes that absorb sunlight and generate high-energy electrons.

Photosystem II

The initial photosystem in light-dependent reactions that absorbs light energy to generate high-energy electrons and splits water ($2 H_2O$) into $4 H^+$ ions, electrons ($4 e^-$), and oxygen ($O_2$).

Electron Transport Chain

A series of electron carrier proteins that shuttle high-energy electrons through the thylakoid membrane during ATP-generating reactions.

Photosystem I

A photosystem where electrons are reenergized by light and transferred through a second electron transport chain to $NADP^+$, forming $NADPH$.

ATP Synthase

A membrane protein complex that spans the thylakoid membrane and utilizes the gradient of passing $H^+$ ions to bind $ADP$ and phosphate together into $ATP$.

Stroma

The fluid-filled space surrounding the thylakoids inside a chloroplast, where light-independent reactions take place.

C4 Plants

Plants that have specialized chemical pathways allowing them to capture low levels of carbon dioxide and perform photosynthesis under extremely bright, hot conditions.

CAM Plants

Plants adapted to dry, hot environments that admit air into their leaves only at night to bind carbon dioxide into organic acids, minimizing daytime water loss.