Photosynthesis: How Plants Make Food

Photosynthesis is the process by which green plants, algae, and some bacteria convert sunlight, water, and carbon dioxide into glucose and oxygen. The green pigment chlorophyll, found in chloroplasts, absorbs sunlight mainly in the blue and red parts of the spectrum.

The overall equation for photosynthesis is: 6CO2 + 6H2O + sunlight -> C6H12O6 + 6O2. In words, six molecules of carbon dioxide and six molecules of water produce one molecule of glucose and six molecules of oxygen.

Photosynthesis happens in two stages. The light-dependent reactions take place in the thylakoid membranes and produce ATP and NADPH while splitting water and releasing oxygen. The Calvin cycle, which takes place in the stroma, uses that ATP and NADPH to fix carbon dioxide into glucose.

Factors that affect the rate of photosynthesis include light intensity, carbon dioxide concentration, and temperature. Farmers and greenhouse growers adjust these factors to improve crop yields.
