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They pass through a series of compounds to photosystem I, losing energy along the way.
Photosystem I, like photosystem II, emits high-energy electrons in the light, and the electrons from photosystem II replace these.
Photosystem II contains chlorophyll molecules. When a photon (quantum of light) reaches one of these chlorophyll molecules, the light energy activates an electron.
This is then passed to the reaction center of the photosystem, where there are two molecules of chlorophyll P680. These pass the electrons to plastoquinone, which, like the chlorophylls, is embedded in the thylakoid membrane. The plastoquinone changes its position within the membrane, and passes the electrons to cytochromes b6 and f.
At this stage the electrons part with a significant proportion of their energy, which is used to pump protons (H+) into the thylakoid lumen. These protons will later be used to generate ATP by chemiosmosis. The electrons now pass to plastocyanin, which is outside the membrane on the lumen side.
Photosystem I is affected by light in much the same way as photosystem II. Chlorophyll P700 passes an activated electron to ferredoxin, which is in the stroma (the liquid outside the thylakoid). Ferredoxin in turn passes the electrons on, reducing NADP+ to NADPH + H+.
Photosystem I accepts electrons from plastocyanin. So, effectively, photosystem II donates electrons to photosystem I, to replace those lost from photosystem I in sunlight.
How does photosystem II recover electrons? When it loses an electron, photosystem II becomes an oxidizing agent, and splits water: 2H2O forms 4H+ + 4e- + O2. The electrons return photosystem II to its original state, and the protons add to the H+ concentration in the thylakoid lumen, for later use in chemiosmosis. The oxygen diffuses away.
What else can I help you with?
Where do electrons get their energy in photosystem I?
In photosystem I, electrons get their energy from the absorption of light by chlorophyll molecules. When light is absorbed, it excites the electrons in the chlorophyll, allowing them to move through a series of electron carriers in the photosystem to generate energy for the production of ATP and NADPH during photosynthesis.
How do electrons gain energy in photosystem I?
They absorb photons.
True or false an electron transport chain connects photosystem 1 and photosystem2?
False. The electron transport chain connects the two photosystems in the thylakoid membrane, but it does not directly connect photosystem 1 and photosystem 2. Instead, it shuttles electrons between the two photosystems as part of the light-dependent reactions of photosynthesis.
Is the energy from sunlight trapped by chlorophyll located in the electron transport chain?
No, the energy trapped by chlorophyll is located in photosystem I and II. Light energy is first captured by PS II and an electron is then transferred to a primary electron acceptor known as plastoquinone. Pq then transfers it's electron to the cytochrome complex that transfers its energy to the electron transport system which passes it on to plastocyanin which in turn gives its electron to PS I where it is re-excited by photons. This process is known as the electron transport but the energy captured by chlorophyll is located in the photosystems.
How do the reaction centers of photosystem you and II differ?
Photosystem 1 has chlorophyll a molecule which absorbs maximum light of 700 nm and is called P700 whereas photosystem 2 has chlorophyll a molecule which absorbs light of 680 nm and is called P680.
What happen to the light energy that is trapped by the chloroplast during the first stage of photosynthesis?
Light energy is not exactly trapped. The light energy excites the electron in the reaction centres of photosystem I and photosystem II. The electron excites and transfers to the electron transport chain ( chain of electron carriers), this produces ATP. Then the electron of photosystem II is transferred by photosystem I and the electron of the photosystem I is used with H+ and NADP to form NADPH. Photosystem II gets back an electron from photolysis of water.
What fills the electron hole in photsystem 1 and 2?
In photosystem 2- water(photolysis) In photosystem 1 - electron from photosystem 2
What happens to electrons when pigments in photosystem II absorbs light?
they move through an electron transport chain to photosystem 1
What happens to electrons when pigments in photosystem absorb lights?
Photosystem's electron travel through the electron transport chain(etc) where ATP is produced and then back to the photosystem. In non-cyclic photophosphorylation, Photosystem II electron then is absorbed by photosystem I, photosystem I electron used to form NADPH and photosystem II gets its electron from photolysis of water. For you unfortunate children using Novanet: They move through an electron transport chain to photosystem 1.
What Is a role in photosystem 1?
In photosystem 1, the role of the reaction center chlorophyll is to absorb photons and initiate the electron transport chain. It passes excited electrons to an electron acceptor, which then moves them through a series of electron carriers to produce NADPH. This process is essential for the conversion of light energy into chemical energy during photosynthesis.
What happens when an excited electron is passed to an electron acceptor in a photosystem?
When an excited electron is passed to an electron acceptor in a photosystem, it creates an electron transport chain that helps generate energy in the form of ATP and NADPH through a series of redox reactions. This process is a crucial step in photosynthesis that ultimately contributes to the production of glucose and other organic molecules.
Where do electrons get their energy in photosystem II?
From energy in photons
What are the reactants and products of photosystem 1?
In Photosystem I (PSI), the primary reactants are light energy, water, and electrons, which are derived from the electron transport chain of Photosystem II. The main products of PSI are NADPH, a reduced electron carrier, and ATP, generated through the associated electron transport processes. The light energy absorbed by PSI drives the transfer of electrons, ultimately leading to the reduction of NADP+ to NADPH.
How does electrons move photosytem II to photosytem?
Electrons move from Photosystem II to Photosystem I through a series of electron carrier molecules in the thylakoid membrane, known as the electron transport chain. During photosynthesis, light energy is used to transfer electrons along this chain, creating a proton gradient that drives ATP synthesis. This process is essential for the production of energy-rich molecules in the form of ATP and NADPH.
An electron transport chain connects photosystem1 and photosystem2?
They return to Photosystem I
Which photosystem is used first in photosynthesis?
Photosystem 2 happens in photosynthesis before photosystem 1. However they are numbered in order of how they were discovered. Photosystem 1 was discovered before photosystem 2. In photosynthesis the order of them is 2 then 1. meaning that photosystem 1 was discovered 1st but photosystem 2 happens 1st in photosynthesis
Where do electrons get their energy in photosystem I?
In photosystem I, electrons get their energy from the absorption of light by chlorophyll molecules. When light is absorbed, it excites the electrons in the chlorophyll, allowing them to move through a series of electron carriers in the photosystem to generate energy for the production of ATP and NADPH during photosynthesis.
