Couldn't find element LayerAd

Error finding content

Photosynthesis - Windows to the Universe

Shop Windows to the Universe

Young Voices for the Planet DVD in our online store includes 8 films where students speak out and take action on climate change.
The leaf is the primary site of photosynthesis in plants.
Click on image for full size
Image has been released into public domain (found on


Photosynthesis is the name of the process by which autotrophs (self-feeders) convert water, carbon dioxide, and solar energy into sugars and oxygen.

It is a complex chemical process by which plants and other autotrophs create the energy needed for biological life. The equation above shows the production of CH2O (formaldehyde), only one of the many carbohydrates that actually form.

The oxygen that is a byproduct of the photosynthesis reaction leaves the plant through the stomata (openings between guard cells on the surface of a plant's epidermis that let in carbon dioxide and let out oxygen). This oxygen is essential in supporting life on Earth.

It is estimated that a full-grown, healthy maple tree has about 500 square feet of leaves weighing about 500 pounds. This represents a total chloroplast surface area of about 140 square miles. Believe it or not, a single maple tree can make two tons of sugar on one good sunny day! (The Way Life Works, Hoagland and Dodson) That's a lot of sugar!

Early bacteria converted solar energy by a different photosynthetic reaction, one which requires an anaerobic environment (one without oxygen), but which produces water as a waste product. The photosynthetic activity of this early bacteria was an interim step in building the oxygen content of Earth's early atmosphere.

The reverse process of photosynthesis is known as respiration. Respiration occurs in all organisms.

Last modified February 8, 2011 by Jennifer Bergman.

Shop Windows to the Universe Science Store!

Traveling Nitrogen is a fun group game appropriate for the classroom. Players follow nitrogen atoms through living and nonliving parts of the nitrogen cycle. For grades 5-9.

Windows to the Universe Community



You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more


Autotrophs are organisms that produce organic compounds from an inorganic source of carbon (carbon dioxide) given a source of energy. If the source of energy is the reactions of inorganic chemical compounds,...more


Respiration is the name of the general process by which living organisms convert sugars and oxygen into biochemical energy. The process occurs in all organisms, including animals, plants, fungi, and bacteria...more

Withering Crops - An Effect of Global Warming

"Though we often take the plants and trees around us for granted, almost every aspect of our lives depends upon them. They feed us, cloth us, absorb carbon dioxide, provide us with oxygen, and give us...more

Exploratour - Life in the Solar System

Life on Earth obtains energy in many types of formats. The two main process are photosynthesis and respiration. Photosynthesis is the name of the process by which autotrophs (self-feeders) convert water,...more

Exploratour: NASA's Exploration for Life

Photosynthesis is the name of the process by which autotrophs (self-feeders) convert water, carbon dioxide, and solar energy into sugars and oxygen. If it weren't for the photosynthetic activity of early...more

Biomes and Ecosystems

Biomes are large regions of the world with similar plants, animals, and other living things that are adapted to the climate and other conditions. Explore the links below to learn more about some of the...more

Iron Ore Deposits

Eventually, as with the development of photosynthesis along sulfur and methane pathways, where sulfur and methane products are produced, photosynthesis along the oxygen pathway, where oxygen is produced,...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF