BLACK BOX summary model for photosynthesis.

Some carotenoids play an energy absorbing role rather than a photosynthetic one.
Carrots, a vegetable rich in b-carotene, help maintain good vision.
xanthophylls pigments in chloroplast membranes that give rise to the yellow colour in autumn leaves.
anthocyanins pigments in vacuoles that give rise to the red colour in autumn leaves
Other accessory pigments ca
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anthocyanins (red, violet, and blue) are primarily located in plant cell vacuoles (not chloroplasts) and are synthesized in the fall in ripening tomatoes or turning maple leaves, for exam
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With the onset of cooler autumn temperatures, plants stop producing chlorophyll molecules and disassemble those already in the leaves.

 We investigate the function of Photosystem II and the mechanism for water oxidation usin.

It turns out that the overall reaction of photosynthesis takes place in two steps. In the first step, the oxygen in water is oxidized by the light energy:


Duringphotosynthesis, electrons are (/added)(to/) water molecules.

You have already studied the "dark reaction" and I will refer you to Dr. Diwan's notes on the subject. As the overall process of photosynthesis involves a series of electron transfer reactions, we are in the realm of oxidation-reduction chemistry, and it would help to review the basics of these processes because we will be going into this topic in greater depth. There is a direct analogy to electron transfer in the mitochondrion, in which clumps of energy are transferred from one electron carrier to another along a "chain" and H+ ions are translocated out, across the mitochondrial membrane, thus generating an electrochemical gradient. The energy inherent in this gradient is used to synthesize ATP in the process of "oxidative phosphorylation." The same processes occur in photosynthesis and the chloroplast, the site of photosynthesis in plants and blue-green algae (but not in photosynthetic bacteria), is the analog of the mitochondrion in eukaryotes.


Manganese Cluster in Photosynthesis: Where Plants Oxidize Water …

Notice that the oxidation state of the carbon atom has changed from +4 to 0, and so an overall reduction reaction has occurred. Here, "(CH2O)" represents a carbohydrate. You'll also notice that there's been a change in the oxidation state of oxygen, since its oxidation state is almost always "-2" when combined with other atoms, but it is "0" in its natural state of O2. So, oxygen (water) is oxidized in the overall process.

What are the different types of photosynthesis? - Quora

Immediatelyafter exposure to 14CO2, the plant's photosynthetic tissue iskilled by immersing it in boiling alcohol, and all of the biochemical reactions cease.

Is carbon dioxide reduced or oxidized during photosynthesis

(4) Photooxidation: Transfer of an electron to an acceptor molecule. In photosynthesis, an excited chlorophyll molecule, Chl*, donates an electron, thereby becoming oxidized to the cationic free radical, Chl+.

During light phase of photosynthesis _____ is oxidized and ..

The energy potential of electrons in water is very low (water is not a reactive solvent) and it is a special metal ion complex (contains manganese) in PSII that has an even lower energy potential for electrons oxidizing water into the radical O. and hydrid H-, two very unstable, reactive intermediates.

Photosynthesis Images Show Splitting of the Water …

Photosystems II and I are coupled by the cytochrom bf complex and the electrons extracted from water by PS II (strong oxidant) and upon photon activation is transported by the electron transport chain via plastoquinone (weak reductant) to the cytochrome bf complex and from there to PS I via plastocyanin (weak oxidant) where it is activated by a photon into activated PS I (strong reductant) which in turn is capable of reducing NADP+.