Photosynthesis: Light Reactions and Calvin Cycle

A set of flashcards covering key concepts and vocabulary related to photosynthesis, focusing on the light reactions and the Calvin cycle.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Light Reactions

The first stage of photosynthesis that takes place in the thylakoid membranes, converting light energy into chemical energy in the form of ATP and NADPH.

Calvin Cycle

The second stage of photosynthesis occurring in the stroma, using ATP and NADPH to convert CO₂ into G3P, a three-carbon sugar.

Chloroplast

An organelle found in plant cells responsible for photosynthesis.

Photosystem I (PSI)

A component of the light reaction that absorbs light best at 700 nm.

Photosystem II (PSII)

A component of the light reaction that absorbs light best at 680 nm.

Rubisco

An enzyme that catalyzes the first step of the Calvin Cycle by fixing carbon dioxide.

NADPH

A high-energy electron carrier produced during light reactions, used in the Calvin Cycle.

G3P

Glyceraldehyde-3-phosphate, a three-carbon sugar produced in the Calvin Cycle.

Chemiosmosis

The process of using a proton (H+) gradient to drive the synthesis of ATP.

Thylakoid Membrane

The membrane that forms thylakoids, where the light-dependent reactions occur.

Stroma

The fluid-filled space surrounding the thylakoids in a chloroplast where the Calvin Cycle takes place.

Photon

A quantum of light energy that is absorbed by pigments in chlorophyll.

ATP Synthase

An enzyme that creates ATP from ADP and inorganic phosphate, powered by the flow of protons.

Light-Harvesting Complexes

Groups of pigment molecules that capture light energy and pass it to the reaction center of a photosystem.

Electron Transport Chain

A series of proteins in the thylakoid membrane that transfer electrons and generate a proton gradient.

Stomata

Small openings on the surface of leaves that allow for gas exchange.

C4 Plant

Plants that have adapted their photosynthesis to minimize water loss in hot, dry climates.

CAM Plant

Plants that fix carbon dioxide at night to reduce water loss.

Starch

A polysaccharide that serves as energy storage in plants.