The electron arrives at photosystem I and joins the P700 special pair of chlorophylls in the reaction center. ... The special pair's missing electron is replaced by an electron from PSII (arriving via the electron transport chain). The high-energy electron travels down a short second leg of the electron transport chain.
How is the electron replaced in photosystem 1?
Photosystem I obtains replacement electrons from the electron transport chain . ATP provides the energy and NADPH provides the hydrogen atoms needed to drive the subsequent photosynthetic dark reaction, or Calvin cycle.
Where are electrons lost from photosystem I replaced from?
Terms in this set (23) How are the electrons lost from photosystem II replaced? Water is split to yield two electrons, with oxygen and two hydrogen ions as by-products. During photosynthesis, electrons are continuously lost from the reaction center of photosystem I .
How electrons lost from photosystem 1 and 2 are replaced?
Electrons lost by Photosystem II are replaced directly by those from water . Electrons lost from P680 (pair of chlorophyll molecules) will be replaced by the splitting of a water molecules, which will generate oxygen as a byproduct.
What is the end product of photosystem I?
ATP is the product of photosystem I.
What is produced in photosystem 1?
Ultimately, the electrons that are transferred by Photosystem I are used to produce the high energy carrier NADPH . The combined action of the entire photosynthetic electron transport chain also produces a proton-motive force that is used to generate ATP.
How does photosystem 2 replace its lost electrons?
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 (O 2 ), which is released into the atmosphere. The hydrogen ions are released into the lumen.
How do photosystems replace lost electrons?
Once an electron is lost, each photosystem is replenished by electrons from a different source . The PSII reaction center gets electrons from water, while the PSI reaction center is replenished by electrons that flow down an electron transport chain from PSII.
What happens after light strikes photosystem I?
Photosynthesis begins when light strikes Photosystem I pigments and excites their electrons . The energy passes rapidly from molecule to molecule until it reaches a special chlorophyll molecule called P700, so named because it absorbs light in the red region of the spectrum at wavelengths of 700 nanometers.
What are photosystem 1 and 2?
Photosystem I (PS I) and photosystem II (PS II) are two multi-subunit membrane-protein complexes involved in oxygenic photosynthesis . ... 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 are the products of photosystem I and II?
| Term Energy Definition The ability to do work | Term Photophosphorylation Definition adding a phosphate to ADP to form ATP using light | Term What are the product(s) of photosystem II? Definition oxygen ATP | Term What are the product(s) of photosystem I? Definition NADPH |
|---|
What is ADP and NADP?
ATP – Adenosine triphosphate . ADP – Adenosine diphosphate . NADP – Nicotinamide adenine dinucleotide phosphate . NADPH – The reduced form of NADP. In the Light Dependent Processes i.e Light Reactions, the light strikes chlorophyll a in such a way as to excite electrons to a higher energy state.
Why is it called P680?
P680 is a group of pigments that are excitonically coupled or that act as if the pigments are a single molecule when they absorb a photon. It derived its name after the wavelength (in nanometers) at which it is best in capturing . In this case, it is the 680 nm of the electromagnetic spectrum.
What is the product of photosystem two?
Photosystem II is the first membrane protein complex in oxygenic photosynthetic organisms in nature. It produces atmospheric oxygen to catalyze the photo-oxidation of water by using light energy. It oxidizes two molecules of water into one molecule of molecular oxygen.
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.
Is oxygen produced in photosystem 1?
Hint: In photosystem I, the electron comes from the transport chain of the chloroplast electron. ... When the electron is removed from the water molecule, the photosystem II separates the water and releases the oxygen gas. This reaction is the source of all the oxygen we breathe.
