What is PSI in photosynthesis?

Photosystem I (PSI) of photosynthesis provides reducing power to reduce NADP to NADPH, which is required for carbon fixation and other synthetic processes.

What is passed from PSII to PSI?

Electron transfer from PSII to PSI takes place via the intersystem electron transfer chain composed of Plastoquinone (PQ), Cytochrome b6f (Cyt b6f), and Plastocyanin (PC). PQ accepts electrons from PSII and the electrons are then transferred to PSI via Cyt b6f and PC.

How do PSI and PSII differ?

The key difference between both the photosystems – Photosystem I and photosystem II is that PS I tends to absorb light of longer wavelengths > 680nm, whereas PS II absorbs light of shorter wavelengths <680 nm.

What does PSII produce?

PSII serves as a light-driven water-plastoquinone oxidoreductase, which extracts electrons from water to fuel the PET chain, and produces molecular oxygen as a by-product.

What are the special features of PS I and PSII?

The main difference between photosystem 1 and 2 is that PS I absorbs longer wavelengths of light (>680 nm) whereas PS II absorbs shorter wavelengths of light (<680 nm).

What happens when PSII is inhibited?

By inhibiting the binding of PQ, the process of photosynthetic electron transfer is interrupted, and the synthesis of ATP and NADPH in the chloroplast is compromised. This results in an inability to fix CO2 and produce the nutrients needed for the plant to survive.

What drives the production of ATP in PSII?

Electron transport through photosystem II is thus coupled to establishment of a proton gradient, which drives the chemiosmotic synthesis of ATP.

What happens in PS II?

PSII is the multisubunit chloroplast membrane-associated pigment–protein complex that uses the energy of sunlight to drive the oxidation of water, evolving oxygen, donating electrons into the photosynthetic electron transfer chain, and depositing protons into the thylakoid lumen.

What is ps1 in photosynthesis?

Photosystem I is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. Ultimately, the electrons that are transferred by Photosystem I are used to produce the moderate-energy hydrogen carrier NADPH.

What is PS II activity?

Abstract. Photosystem II (PSII) is a membrane protein complex which functions to catalyze light-induced water oxidation in oxygenic photosynthesis.

How PS II is continuously supplied with electrons during light reaction?

PS II supplies electrons continuously by the splitting of water molecules. The water-splitting complex is associated with PS II on the inner membrane of the thylakoid. The water-splitting leads to the synthesis of oxygen, protons and electrons.

How do PSII inhibitors work?

Blocking electron transport in PSII systems promotes the formation of highly reactive molecules that initiate a chain of reactions causing lipid and protein membrane destruction that results in membrane leakage allowing cells and cell organelles to dry and rapidly disintegrate.

What does PSII do in photosynthesis?

Photosystem II (PSII) is a membrane protein supercomplex that executes the initial reaction of photosynthesis in higher plants, algae, and cyanobacteria. It captures the light from the sun to catalyze a transmembrane charge separation.

What is ps1 and PS2 in photosynthesis?

PS I and PS II are the two photosystems which drive the light reaction of photosynthesis. The first stage of the light reaction occurs in PS II whereas the final stage of the light reaction occurs in PS I. Each of the two photosystems are made up of a collection of proteins and pigments.

What is P700 absorption maxima?

In PS-II the reaction centre chlorophyll-a a) has an absorption peak at 700 nm hence, is called P700 In PS-I the reaction centre chlorophyll-a has b) an absorption maxima at 680 nm and is called P680 c) The spitting of water molecule is associated with PS-1 d) Photosynthems-I and II are involved in Z scheme.