Level of life
Cell
The smallest unit that can live on its own. Every living thing is made of one or more cells.
Capture light energy to make sugar by photosynthesis.Source: OpenStax, 2018Source: Archibald, 2015Source: Bar-On & Milo, 2019
Level of life
The smallest unit that can live on its own. Every living thing is made of one or more cells.
Process
Using light energy to turn carbon dioxide and water into sugar, releasing oxygen.
Organism or group
Small single-celled organisms without a nucleus, found almost everywhere on Earth. Most bacteria in the human body are harmless, and some are helpful.
Idea or model
Mitochondria and chloroplasts descend from bacteria that came to live inside other cells long ago.
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
OpenStax (2018). OpenStax, Rice University.
Free introductory college textbook.
Licence: CC BY-NC-SA 4.0 (linked, not reused)
Archibald JM (2015). Current Biology 25:R911-R921.
Bar-On YM, Milo R (2019). Proceedings of the National Academy of Sciences 116:4738-4743.
Estimates about 0.7 gigatonnes of rubisco on Earth, mostly in land plant leaves.