Photosynthesis
Definition and meaning of Photosynthesis in chemistry.
Photosynthesis is a biological and chemical process used by plants, algae, and certain bacteria to convert light energy into chemical energy stored in glucose. The overall reaction transforms carbon dioxide and water into glucose and oxygen gas using the energy from sunlight.
In more detail
The process occurs in two main stages within the chloroplasts of plant cells, specifically the light-dependent reactions and the light-independent reactions known as the Calvin cycle. During the light-dependent reactions, chlorophyll absorbs photons, driving the photolysis of water into oxygen, protons, and electrons, and generating ATP and NADPH. The Calvin cycle then uses these high-energy molecules to fix carbon dioxide from the atmosphere into a three-carbon sugar, which is eventually converted into glucose. Photosynthesis is the primary source of organic matter on Earth and is responsible for maintaining atmospheric oxygen levels. The balanced chemical equation is 6CO2 + 6H2O -> C6H12O6 + 6O2.
Key facts
| Field | Biochemistry |
|---|---|
| Formula | C6H12O6 |
| Molar mass | 180.16 g/mol |
| Key enzyme | RuBisCO |
| Primary pigment | Chlorophyll a |
| Cellular location | Chloroplasts |
A sunflower utilizes sunlight to synthesize glucose, providing the necessary energy for its cellular respiration, growth, and the production of cellulose for its cell walls.
Frequently asked questions
What is the role of chlorophyll in photosynthesis?
Chlorophyll is a green pigment that absorbs light energy, primarily in the blue and red wavelengths, initiating the electron transport chain required to produce ATP and NADPH.
Do plants perform photosynthesis at night?
The light-dependent reactions cease without sunlight, but the Calvin cycle can continue briefly in the dark until the supply of ATP and NADPH is depleted.