Photosynthesis
The process plants use to convert sunlight, water, and CO2 into glucose and oxygen.
Definition
Photosynthesis is the biological process by which plants, algae, and some bacteria convert light energy, water, and carbon dioxide into glucose and oxygen. It occurs in two main stages: the light-dependent reactions in the thylakoid membranes that capture solar energy, and the Calvin cycle in the stroma that fixes carbon dioxide into sugar. Photosynthesis is the foundation of most food webs on Earth.
Example
“A sunflower absorbs sunlight through its leaves, draws water from the soil through its roots, and pulls carbon dioxide from the air through stomata, producing the glucose that fuels its growth and the oxygen we breathe.”
Usage Examples
- 1
“The biology students measured how light intensity affected the rate of photosynthesis by counting oxygen bubbles released by aquatic plants.”
- 2
“Photosynthesis underpins all food chains — without it, virtually no life on Earth could exist.”
When & How to Use
Use when explaining how plants, algae, and cyanobacteria convert light energy, carbon dioxide, and water into glucose and oxygen.
- ▸Calculating the oxygen output of a given area of forest for carbon sequestration reports
- ▸Optimising greenhouse lighting to maximise crop photosynthesis rates
- ▸Explaining why deforestation accelerates climate change by reducing CO₂ absorption
Etymology & Origin
Greek 'phos' (light) + 'synthesis' (putting together). The term was introduced by C.B. van Niel in 1931, though the process was studied since Jan Ingenhousz demonstrated in 1779 that plants produce oxygen in light.
History & Evolution
Joseph Priestley (1772) discovered plants restore air made impure by combustion. Ingenhousz (1779) showed light was essential. The chemical equation was fully elucidated in the 20th century; the Calvin cycle was described by Melvin Calvin (Nobel Prize, 1961).
Synonyms
- carbon fixation
- solar energy conversion
- light-driven synthesis
Antonyms / Opposites
- cellular respiration
- decomposition
Images
CC-licensed · free to useVideo
Related Terms
- Cellular Respiration
- Chloroplast
- Calvin Cycle
- Glucose