Q. Did photosystem 1 or 2 evolve first?
Which photosystem–I or II– most likely evolved first? Photosystem II because when the photosystem II loses electrons, they are quickly replaced by electrons from water. Photosystem I relies on photosystem II to feed it electrons, so photosystem I most likely evolved AFTER photosystem II.
Q. Which photosystem is used first in photosynthesis?
Physically, photosystems are found in the thylakoid membranes. There are two kinds of photosystems: photosystem I (PSI) and photosystem II (PSII) (Fig. 3.3). PSII acts first during the light transformation process in photosynthesis, but it was named PSII because it was discovered second.
Q. Which photosystem comes first in light reactions?
photosystem II
Q. What occurs in the first photosystem?
The light reaction occurs in two photosystems (units of chlorophyll molecules). 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.
Q. What is the difference between photosystem I and photosystem II quizlet?
What is the difference between Photosystem II and Photosystem I? Photosystems II and I have different chlorophylls. PS II has P680 and PS I has P700. Photosystem II comes before Photosystem I.
Q. What is the overall function of photosystem 1?
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 high energy carrier NADPH.
Q. What is found in photosystem?
Each photosystem has two parts: a reaction center, where the photochemistry occurs, and an antenna complex, which surrounds the reaction center. The antenna complex contains hundreds of chlorophyll molecules which funnel the excitation energy to the center of the photosystem.
Q. What is ps1 and ps2 in photosynthesis?
Each photosystem consists of a light-harvesting complex and a core complex. Each core complex contains a reaction centre with the pigment (either P700 or P680) that can be photochemically oxidized, together with electron acceptors and electron donors.
Q. How ATP is formed in photosynthesis?
The Light Reactions of Photosynthesis. Light is absorbed and the energy is used to drive electrons from water to generate NADPH and to drive protons across a membrane. These protons return through ATP synthase to make ATP.
