photosynthesis refresher

Photon

A packet of light.

Chlorophyll

The light-absorbing green-coloured pigment that begins the process of photosynthesis.

Chloroplast

A membrane-bound organelle in green plant and algal cells that carries out photosynthesis.

Stroma

The protein-rich semiliquid material in the interior of a chloroplast.

Thylakoid

A disk-shaped sac in the stroma of a chloroplast.

Grana

Stacks of tylakoids.

Lamellae

Groups of unstacked thylakoids between grana.

Thylakoid Membrane

The photosynthetic membrane within a chloroplast that contains light gathering pigment molecules and electron transport chains.

Thylakoid Lumen

A fluid-filled interior space enclosed by the thylakoid membrane.

ATP

A molecule containing three high energy phosphate bonds that acts as the primary energy-transferring molecule in a living organism.

ADP

A molecule containing two high-energy phosphate bonds that may be formed by breaking one of the phosphate bonds in ATP.

NADP+

A compound that accepts one hydrogen atom and two electrons forming NADPH; it is an electron acceptor.

NADPH

A compound that donates one hydrogen aton and two electrons to another molecule, to reform NADP+; it is an electron donor.

Light-dependent reactions

reactions of photosynthesis that use energy from light to produce ATP and NADPH

Carbon Fixation

The process of incorporation CO2 into carbohydrate molecules.

Calvin Cycle

A cyclic set of reactions occurring in the stroma of chloroplasts that fixes the carbon of CO2 into carbohydrate molecules and recycles coenzymes.

Light-independent reactions

The second set of reactions in photosynthesis that do not require light.

Photosystem

A cluster of photosynthetic pigments embedded in a thylakoid membrane of a chloroplast that absorbs light energy.

Electron Transport Chain

A series of progressively stronger electron acceptors; each time an electron is transferred, energy is released.