Photosystem
Photosystem[edit | edit source]
A photosystem is a complex of proteins and pigments found in the thylakoid membrane of chloroplasts in plants, algae, and cyanobacteria. Photosystems are essential components of the photosynthesis process, where they play a critical role in the light-dependent reactions.
Structure[edit | edit source]
Photosystems are composed of a reaction center surrounded by numerous antenna pigments. The reaction center contains a special pair of chlorophyll molecules that are capable of undergoing oxidation and reduction. The antenna pigments, which include various types of chlorophyll and carotenoids, capture light energy and transfer it to the reaction center.
Types of Photosystems[edit | edit source]
There are two main types of photosystems: Photosystem I (PSI) and Photosystem II (PSII). Each type has a distinct role in the light-dependent reactions of photosynthesis.
Photosystem II[edit | edit source]
Photosystem II is the first complex in the sequence of the light-dependent reactions. It absorbs light energy and uses it to extract electrons from water molecules, releasing oxygen as a byproduct. The electrons are then passed through a series of proteins in the electron transport chain, ultimately reaching Photosystem I.
Photosystem I[edit | edit source]
Photosystem I absorbs light energy and uses it to further energize the electrons received from Photosystem II. These high-energy electrons are then used to reduce NADP+ to NADPH, which is a crucial molecule for the Calvin cycle in the light-independent reactions of photosynthesis.
Function[edit | edit source]
The primary function of photosystems is to convert light energy into chemical energy. This is achieved through the absorption of photons by the antenna pigments, which then transfer the energy to the reaction center. The energized electrons from the reaction center are used to drive the synthesis of ATP and NADPH, which are essential for the subsequent stages of photosynthesis.
Location[edit | edit source]
Photosystems are located in the thylakoid membranes of chloroplasts. The thylakoid membrane is a highly organized structure that facilitates the efficient capture and conversion of light energy.
Related pages[edit | edit source]
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
|
WikiMD's Wellness Encyclopedia |
| Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates, categories Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD
