Close

2021-05-15

What replaces the electrons that are lost by energized photosystem I?

What replaces the electrons that are lost by energized photosystem I?

A pigment molecule in the photosystem absorbs one photon, a quantity or “packet” of light energy, at a time. To replace the electron in the chlorophyll, a molecule of water is split. This splitting releases an electron and results in the formation of oxygen (O2) and hydrogen ions (H+) in the thylakoid space.

How are the electrons replaced when they are energized and lost from photosystem II?

The two electrons lost from photosystem II are replaced by the splitting of water molecules. It is here that photons again energize each electron and propel their transfer to ferredoxin. Ferredoxin then transfers the electrons to the ferredoxin-NADP-reductase, also known as FNR.

What happens to the energy of the electrons that travel down the electron transport chain between photosystem II and photosystem I?

In the photosystem II (PSII) reaction center, energy from sunlight is used to extract electrons from water. The electrons travel through the chloroplast electron transport chain to photosystem I (PSI), which reduces NADP+ to NADPH. The electron transport chain moves protons across the thylakoid membrane into the lumen.

What happens when light energy excites electrons in photosystem II?

What happens when light energy excites electrons in photosystem II? Electrons are released into the electron transport system.

What happens when a photon of light hits photosystem II?

When a photon hit photosystem II, light energy absorbed by one of the pigments in photosystem II, energy is carried from one pigment to another and reach down to the reaction center . NADPH formation.

What is the main 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.

What is the purpose of photosystems I and II?

Photosystems are the functional units for photosynthesis, defined by a particular pigment organization and association patterns, whose work is the absorption and transfer of light energy, which implies transfer of electrons. There are two kinds of photosystems: photosystem I (PSI) and photosystem II (PSII) (Fig. 3.3).

What happens in carbon fixation in Calvin cycle?

In the Calvin cycle, carbon atoms from CO2​start text, C, O, end text, start subscript, 2, end subscript are fixed (incorporated into organic molecules) and used to build three-carbon sugars. This process is fueled by, and dependent on, ATP and NADPH from the light reactions.