Photosystem I vs. Photosystem II
Main DifferenceA photosystem is a process in plants and other organisms to absorb sunlight and use it as a source of energy; this system enables plants to convert light energy into chemical energy. There are two photosystems in the thylakoid membrane of chloroplasts of leaves in plants. These are Photosystem I and Photosystem II. Photosystem I is the system that absorbs light photons of the wavelength of 700nm, whereas photosystem II absorbs the photons of the wavelength of 680nm. Photosystem I is so named because it was discovered first and photosystem II was discovered later. But if we see their function, photosystem II comes before photosystem I. The only major difference between photosystem I and photosystem II is of the wavelength of light that is absorbed by it. However, both are having equal importance in the process of photosynthesis.
Difference Between Photosystem I and Photosystem II
Photosystem I vs. Photosystem II
Photosystem I absorbs light of 700nm wavelengths, whereas photosystem II absorbs light of 680nm wavelengths.
Photosystem I vs. Photosystem II
Photosystem I has active center P700 while photosystem II has active center
Photosystem I vs. Photosystem II
Photosystem I is involved in cyclic and non-cyclic photophosphorylation, whereas photosystem II is involved only in non-cyclic photophosphorylation.
Photosystem I vs. Photosystem II
The main function of photosystem I is synthesizing of ATP, on the other hand, the main function of photosystem II is synthesizing of ATP and photolysis of water.
Photosystem I vs. Photosystem II
Photosystem I is located at the outer surface of grana of thylakoid while, photosystem II is located in at the inner surface of grana of thylakoid.
Photosystem I vs. Photosystem II
Photosystem I has larger binding proteins, whereas photosystem II, has smaller binding proteins.
Comparison Chart
| Photosystem I | Photosystem II |
| Photosystem I absorbs light of 700nm wavelengths. | Photosystem II absorbs light of 680nm wavelengths. |
| Active Center | |
| Photosystem I has active center P700. | Photosystem II has active center P680. |
| Photophosphorylation | |
| Photosystem I is involved in cyclic and non-cyclic photophosphorylation. | Photosystem II is involved only in non-cyclic photophosphorylation. |
| Main Function | |
| The main function of photosystem I is the synthesis of ATP. | The main function of photosystem II is a synthesis of ATP and photolysis of water. |
| Located At | |
| Photosystem I is located at the outer surface of grana of thylakoid. | Photosystem II is located in at the inner surface of grana of thylakoid. |
| Binding Proteins | |
| Photosystem I has larger binding proteins. | Photosystem II has smaller binding proteins. |
What is Photosystem I?
Photosystem I is one of the systems of photosystems involved in photosynthesis. Photosystem I is so named because it was discovered first and photosystem II was discovered later.
Photosystem I is located at the outer surface of grana of thylakoid. Photosystem I is a complex of collections of proteins. It is sensitive to light, and it absorbs light of about 700nm. Its pigments absorb light and use it as a source of energy. And it is not associated with photolysis of water. Here light energy is converted into chemical energy and finally used in the process of photosynthesis. The main function of photosystemI is synthesizing of ATP. Photosystem I is involved in cyclic and non-cyclic photophosphorylation. Photosystem I includes following pigments:
- Chlorophyll -a 670
- Chlorophyll -a 680
- Chlorophyll -a 695.
- Chlorophyll -a 700.
- Chlorophyll b
What is Photosystem II?
Photosystem II is one of a system of photosystems involved in photosynthesis. Photosystem II was discovered later. But if we see their function, photosystem II comes before photosystem I. Photosystem II is located in at the inner surface of grana of thylakoid. Photosystem II has a smaller binding protein as compare to photosystem I that has MW of 110,000. It absorbs light of about 680nm. Its pigments absorb light and use it as a source of energy. And it is associated with photolysis of water. Here light energy is converted into chemical energy and finally used in the process of photosynthesis. The main function of photosystem II is the synthesizing of ATP and photolysis of water. Photosystem II is involved only in non-cyclic photophosphorylation.
Photosystem II includes following pigments:
- Chlorophyll -a 660
- Chlorophyll -a 670
- Chlorophyll -a 680.
- Chlorophyll -a 695.
- Chlorophyll -a 700.
- Chlorophyll
