Applied Science
Material Type:
Rice University
Provider Set:
OpenStax College
ADP, ATP, Absorption, Absorption Spectrum, Antenna Molecule, Autotroph, Calvin Cycle, Calvin-Benson Cycle, Carbon Fixation, Chemosynthetic Organism, Chlorophyll, Chlorophyll a, Chlorophyll b, Chloroplast, Cytochrome Complex, Dark Reaction, Electromagnetic Spectrum, Electron Transport Chain, Energy, Energy Cycle, Fixation, Food Production, Grana, Granum, Heterotroph, Light Energy, Light Wavelengths, Light-dependent Reaction, Light-independent Reaction, Mesophyll, NADP, NADPH, Organic Molecule, Photoautotroph, Photon, Photosynthesis, Photosynthesis Products, Photosynthesis Reactants, Photosystem I, Photosystem II, Pigment, Primary Electron Acceptor, Prokaryote, Reaction Center, Reduction, Regeneration, RuBP, RuBisCO, Solar Dependence, Stomata, Stroma, Thylakoid, Visible Light, Wavelength
Creative Commons Attribution


The image shows a map of the world, colored by the levels of chlorophyll a on land and in the ocean.
This world map shows Earth’s distribution of photosynthetic activity determined by chlorophyll a concentrations. On land, chlorophyll is evident from terrestrial plants, and within oceanic zones, from chlorophyll from phytoplankton. (credit: modification of work by SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE)

The metabolic processes in all organisms—from bacteria to humans—require energy. To get this energy, many organisms access stored energy by eating, that is, by ingesting other organisms. But where does the stored energy in food originate? All of this energy can be traced back to photosynthesis.