Happy Birthday, Jan Ingenhousz
This Dutch scientist discovered photosynthesis and also discovered that plants, like animals, have cellular respiration. Those are major, major discoveries—but not what he was best known for in his own lifetime. His claims to fame were his successful inoculation of the royal Habsburg family of Austria and his post as the doctor of the Empress Maria Theresa.
Ingenhousz did a lot of work in biology and chemistry in at least six different European countries and met an important American, Benjamin Franklin.
Photosynthesis is the process by which plants use the energy in sunlight to convert carbon dioxide and water into sugars and oxygen. In other words, it is the process by which plants makes their own food!
Actually, plants don't just make their own food—the photosynthesis of plants, some bacteria, and algae creates the basis of almost all food chains and therefore form the foundation of almost all life on earth—providing both food and oxygen for animals.
Also, listen to Peter Weatherall's song about photosynthesis.
Photosynthesis starts in chloroplasts inside plant cells.
Cellular respiration is pretty much the opposite of photosynthesis. It is the process by which plant and animal cells break down food (such as sugars) in order to obtain energy. The process requires oxygen.
Find out more at Biology 4 Kids.
Here is a straightforward video about respiration and photosynthesis.
Respiration occurs inside cells' mitochondria.
Photosynthesis — carbon dioxide + water + energy (sunlight) = sugar + oxygen
Respiration — sugar + oxygen = carbon dioxide + water + energy (to grow or move or repair cells or reproduce)
Ready for one more song about both photosynthesis and cellular respiration? Here it is.