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Are the chlorophyll molecules in PSI and PSII the same?
No, the chlorophyll molecules in Photosystem I (PSI) and Photosystem II (PSII) are not the same. They differ in absorption spectra and redox properties, allowing them to play distinct roles in the light reactions of photosynthesis.
Where do electrons for photosystem II come from?
Electrons for photosystem II come from the splitting of water molecules during the light-dependent reactions of photosynthesis. This process, known as photolysis, occurs in the thylakoid membranes of chloroplasts. The electrons released from water molecules replace those lost by chlorophyll molecules in photosystem II, allowing the photosystem to continue the electron transport chain and ultimately produce ATP and NADPH for the Calvin cycle.
Where do the electron get their energy in photosystem 1?
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.
Which is role of photosystem in the light reactions?
to make energy-carrier molecules like NADPH Apex
Which complex or enzyme of photosynthesis consumes h2o?
The complex known as Photosystem II in the thylakoid membrane of chloroplasts is responsible for splitting water (H2O) into oxygen, protons (H+), and electrons during the light-dependent reactions of photosynthesis. This process provides the electrons needed to generate ATP and NADPH for use in the Calvin cycle.
What is the cluster of light harvesting complexes in a thylakoid?
The cluster of light harvesting complexes in a thylakoid is called a photosystem. It consists of chlorophyll molecules and other pigments that absorb light energy and transfer it to reaction centers where photosynthesis takes place. Photosystem I and Photosystem II are the two main types found in the thylakoid membrane.
Which is a reactant is for the reaction that is powered by sun hitting photosystem II?
ADP
Which is a role of photosystem ii in the light reaction?
Splitting H2O (Apex)
Which is a reactant for the reaction that is powered by sun hitting photosystem II?
Water is the reactant for the reaction powered by the sun hitting photosystem II. This reaction leads to the splitting of water molecules to release oxygen, protons, and electrons in the process of photosynthesis.
Why did photosystem II evolve first?
This is a speculative area! The most detailed studies and reasoning relevant to this question are perhaps those of Nathan Nelson, who has used genomic analyses of Eubacteria, Archaea, and eukaryotes to draw up a tentative evolutionary tree of photosynthetic reaction centers. His conclusion is that photosystems I and II, or rather, reaction centers of these two types, had a common origin about 2.5 Ga (billion years ago). - - - photosystem II - - - It was Kodak that invented the first, ever, photosystem for every man to use. In those days you needed to buy the camera and after having taken all the shots, you simply returned the camera (intact) to Kodak. Kodak would then make prints of your photos and return it. --- But I think you meant the photosystem used in photosynthesis lol photosystem 1 was discovered first, but it does not mean that it evolved first. Photosystem 2 is actually first in the process of capturing light energy. But as you can see, the answer is mainly a mystery, just like "Which came first, the chicken or the egg?" Hope this helped --
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.
Photosystem 1 and photosystem 2?
Photosystem I and II are two types of reaction centers found in thylakoid membranes, which are the sites of protein synthesis located in the leaves of plants. The function of reaction centers is to convert light energy into chemical energy (photophosphorylation). Now the difference between photosystem I and photosystem II is that each is able to absorb a particular wavelength. Photosystem 2 has a maximum absorption at a wavelength of 680 nanometers. Photosystem 1 best absorbs light at a wavelength of 700 nanometers. Hope this helps!
Which steps occur in photosystem II?
ADP takes on energy and a phosphate to produce ATP in photosystem II.
What is the waters role in the reaction of photosynthesis?
Water is split to have its electrons replace the excited electron of chlorophyll, then enters photosystem II.
What is the difference between photosystem one and two?
Photosystem I absorbs light best at a wavelength of 700 nm, while Photosystem II absorbs light best at a wavelength of 680 nm. Photosystem I transfers electrons to reduce NADP+ to NADPH, while Photosystem II replenishes electrons lost in the process of photosynthesis. Both photosystems work together in the light-dependent reactions of photosynthesis to ultimately produce ATP and NADPH.
What is the waters role in the light reaction of photosynthesis?
Water is split to have its electrons replace the excited electron of chlorophyll, then enters photosystem II.
Are the chlorophyll molecules in PSI and PSII the same?
No, the chlorophyll molecules in Photosystem I (PSI) and Photosystem II (PSII) are not the same. They differ in absorption spectra and redox properties, allowing them to play distinct roles in the light reactions of photosynthesis.
