What is the significance of photosystem II plants?
Photosystem II (PSII) is a multi-subunit pigment-protein complex found in thylakoid membranes of oxygenic photosynthetic organisms, including cyanobacteria, algae, and plants (Nickelsen and Rengstl, 2013; Järvi et al., 2015). Driven by light, PSII catalyzes electron transfer from water to plastoquinone.
What is the main function of photosystem II?
The most important function of photosystem II (PSII) is its action as a water-plastoquinone oxido-reductase. At the expense of light energy, water is split, and oxygen and plastoquinol are formed.
What is a byproduct of photosystem II?
Photosystem II obtains replacement electrons from water molecules, resulting in their split into hydrogen ions (H+) and oxygen atoms. The oxygen atoms combine to form molecular oxygen (O2), which is released into the atmosphere.
What is Photoinhibition in plants?
Photoinhibition of photosynthesis is defined as a persistent decrease in the efficiency of solar energy conversion into photosynthesis in combination with a decreased overall capacity for photosynthesis.
What happens in photosystem II?
Photosystem II is the first link in the chain of photosynthesis. It captures photons and uses the energy to extract electrons from water molecules. First, when the electrons are removed, the water molecule is broken into oxygen gas, which bubbles away, and hydrogen ions, which are used to power ATP synthesis.
What happens during photosystem II?
Does photosystem 2 produce ATP?
Electrons are transferred sequentially between the two photosystems, with photosystem I acting to generate NADPH and photosystem II acting to generate ATP. Electron transport through photosystem II is thus coupled to establishment of a proton gradient, which drives the chemiosmotic synthesis of ATP.
Why is it called cyclic Photophosphorylation?
The photophosphorylation process which results in the movement of the electrons in a cyclic manner for synthesizing ATP molecules is called cyclic photophosphorylation. During cyclic photophosphorylation, the electrons are transferred back to P700 instead of moving into the NADP from the electron acceptor.
What happens if photosystem 1 is inhibited?
Herbicides that inhibit Photosystem I are considered to be contact herbicides and are often referred to as membrane disruptors. The end result is that cell membranes are rapidly destroyed resulting in leakage of cell contents into the intercellular spaces.
What happens if photosystem 1 is blocked?
Herbicides that inhibit Photosystem I are considered to be contact herbicides and are often referred to as membrane disruptors. The end result is that cell membranes are rapidly destroyed resulting in leakage of cell contents into the intercellular spaces. See chemical structure shown under herbicide families.
What is the difference between photosystem I and II?
Photosystem I is very receptive to light waves at the 700 nm wavelength. In comparison, photosystem II is very receptive to light wavelengths of around 680 nm. Both photosystem I and II are necessary in most plants to produce the energy they need from the sun.
What is the Photoinhibition of photosystem II ( PSII )?
Photoinhibition of Photosystem II (PSII) is the light-induced loss of PSII electron-transfer activity. Although photoinhibition has been studied for a long time, there is no consensus about its mechanism.
Is there a consensus about the mechanism of photoinhibition?
Although photoinhibition has been studied for a long time, there is no consensus about its mechanism. On one hand, production of singlet oxygen ( (1)O (2)) by PSII has promoted models in which this reactive oxygen species (ROS) is considered to act as the agent of photoinhibitory damage.
Is the plant PSI susceptible to photoinhibition?
Although the photoinhibition of PSI could be induced only in specific conditions and specific plant species in intact leaves, PSI itself is quite susceptible to photoinhibition in isolated thylakoid membranes. PSI seems to be well protected from photoinhibition in vivo in many plant species and many environmental conditions.
How does Ros inhibit the repair of photodamaged PSII?
By contrast, in a new scheme, we propose that photodamage is initiated by the direct effect of light on the oxygen-evolving complex and that ROS inhibit the repair of photodamaged PSII by suppressing primarily the synthesis of proteins de novo. The activity of PSII is restricted by a variety of environmental stresses.