Photosystems in Plant Cells: Transferring Excited Electron Energy

In summary, the energy of an excited electron in the photosystem of chloroplasts is transferred between amino acid residues, such as Tyrosine, and then on to reduce plastoquinone. This electron transport ensures that the electron goes to the correct location. In the antenna complex, the electron is physically transferred from chlorophyll P680 to pheophytin, and then received by tyrosine from a cluster of manganese ions in the oxygen-evolving complex. This transfer of electrons results in the reduction of two water molecules to form one oxygen molecule.
  • #1
mahela007
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How is the energy of an excited electron sent to another adjacent molecule as in the photosystem of chloroplasts in plant cells?
 
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  • #2


Depends on which exact part you mean. Within PS2 it gets transferred between amino acid resides (e.g. Tyrosine) and on to reduce plastoquinone, which is what serves as the 'electron transport' to the next enzyme in the chain.

Electrons can't be allowed to move freely in the solution/cytoplasm, or they'd zoom off and reduce whatever was most reducible. So you have all these electron-transporting molecules and enzymes, to make sure the right electron goes to the right place.
 
  • #3


Thanks for your reply... I'm talking about the antenna complex which "funnels" light energy to the reaction center chlorophyll.. how is energy transferred from one chlorophyll to another adjacent chlorophyll? The electron isn't physically transferred.. I'm interested in knowing how the energy of an excited electron is handed over to a separate molecule..
 
  • #4


The electron is physically transferred. The excitation from light kicks out an electron from the chlorophyll P680, which goes off to pheophytin.

P680+ then gets an electron from a tyrosine, which in turn gets it from a cluster of manganese ions in the oxygen-evolving complex. Four photons makes for four electrons which results in two water molecules being reduced to an oxygen molecule.
 
  • #5


my textbook says the electron is not transferred... :-|
 

What are photosystems in plant cells?

Photosystems are specialized protein complexes located in the thylakoid membrane of plant cells. They are responsible for capturing and transferring light energy during the process of photosynthesis.

How do photosystems transfer excited electron energy?

Photosystems contain pigments, such as chlorophyll, that are able to absorb light energy. When light is absorbed, electrons within the pigments become excited and are transferred to a series of electron carriers within the photosystem. These carriers then use the energy from the excited electrons to produce ATP and NADPH, which are essential molecules for the conversion of light energy into chemical energy.

What is the difference between Photosystem I and Photosystem II?

Photosystem I and Photosystem II are two types of photosystems found in plant cells. Photosystem II is responsible for capturing light energy and transferring electrons to Photosystem I, while Photosystem I uses the electrons to produce NADPH. Photosystem II also produces ATP through a process called photophosphorylation, while Photosystem I does not.

How do photosystems play a role in the process of photosynthesis?

Photosynthesis is the process by which plants convert light energy into chemical energy. Photosystems play a crucial role in this process by capturing light energy and using it to produce ATP and NADPH. These molecules are then used to power the Calvin cycle, which converts carbon dioxide into glucose, the primary source of energy for plants.

Can photosystems be affected by environmental factors?

Yes, photosystems can be affected by various environmental factors, such as light intensity, temperature, and water availability. Changes in these factors can impact the efficiency of photosynthesis and the production of ATP and NADPH by photosystems. In some cases, excessive exposure to light can even damage the photosystems and hinder their ability to function properly.

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