Photosynthesis

Unit 8 Photosynthesis

Autotrophs

Organisms that can use the sun to create food.

Heterotrophs

Organisms that must get energy from the food they eat.

Photosynthesis

A series of complex chemical reactions that converts light energy from the sun into chemical energy in the form of organic compounds.

Light Reactions

The first stage of photosynthesis where light energy is captured, and chemical energy is stored.

Calvin Cycle

A series of enzyme-assisted chemical reactions that creates organic compounds from carbon dioxide.

Chloroplast

An organelle in plant cells where photosynthesis occurs.

Thylakoids

A system of membranes arranged as flattened sacs where photosynthesis takes place.

Pigments

Compounds that absorb light, critical for the process of photosynthesis.

Chlorophyll a

The main photosynthetic pigment that absorbs light energy.

Chemiosmosis

The process by which ATP is generated in the light reactions, utilizing the concentration gradient of protons.

ATP (Adenosine Triphosphate)

The main energy currency of the cell.

NADPH

An electron carrier created during the light reactions of photosynthesis.

Carbon Fixation

The process of converting inorganic carbon dioxide into organic compounds.

C4 Pathway

A form of carbon fixation in plants that partially closes their stomata and functions with low CO2 levels.

CAM Pathway

A water-conserving pathway in plants that opens stomata at night to prevent water loss.

Stomata

Small pores in the leaf through which carbon dioxide enters.

Grana

Stacks of thylakoids within chloroplasts where light reactions occur.

Lumen

The space inside the thylakoids.

Primary Electron Acceptor

A molecule that accepts excited electrons from chlorophyll during the light reactions.

Electron Transport Chain (ETC)

A series of molecules that transfer electrons during the light reactions.

Oxygen (O2)

A product of photosynthesis that is released into the atmosphere.