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These stages are called the light reactions and the dark reactions.

The chloroplast contains thykaloids, disks in which the light reactions of photosynthesis take place.

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The light reactions take place in the presence of light.

NADPH and the hydrogen ions made in the light reactions are used to split a phosphate off of each (putting phosphates back to make more ATP) and to provide the energy and hydrogen to turn the remaining chemical into glyceraldehyde phospate, also called phosphoglyceraldehyde, or PGAL.

This reaction occurs in two sections, which we'll call light reactions and dark reactions.

This reaction doesn't directly need light in order to occur, but it does need the products of the light reaction ATP and another chemical called NADPH.

In the light-independent (or "dark") reactions, ..

The dark reaction involves a cycle called the Calvin cycle in which CO2 and energy from ATP are used to form sugar.

It is also noteworthy that in acidic environments phosphate ions react with Iron and make iron less soluble and thus less available. Therefore if one require more iron, slightly alkaline values are more desirable.

Both ATP and NADPH are used in the dark reactions to produce sugar.

Dark Reaction
The dark reaction takes place in the stroma within the chloroplast and converts CO2 to sugar.

Dark Reactions of Photosynthesis: The Calvin-Benson …

The Light Reaction

Our research efforts focus on designing and characterizing molecular and inorganic components that carry out the various functions of natural Photosystems I and II: (a) light absorption and charge separation by band-gap narrowed semiconductors (BGNSCs) and transition metal complexes as chromophores, (b) the water oxidation half-reaction to produce protons and electrons using molecular catalysts and metal oxides, (c) the transport of protons and electrons, and (d) reduction half-reactions that convert these protons and/or carbon dioxide into fuels using molecular catalysts and all-inorganic catalysts, with the ultimate goal of integrating these components into artificial systems that convert sunlight into fuels. These components and their relationship to PS I and PS II are shown schematically in the diagram below

The Light Reactions(4.1) In the chemical reaction for photosynthesis, six molecules of water and six molecules of carbon dioxide react in the presence of chlorophyll and sunlight to produce one molecule of sugar plus six molecules of oxygen.

Photosythesis- Light and dark reactions detailed - …
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  • Light and dark reactions in photosynthesis ..

    This fact allows measurement of the light reaction of photosynthesis by using chlorophyll fluorometers.

  • Dark reactions make use of these organic energy molecules ..

    05/05/2017 · Photosythesis- Light and dark reactions detailed Steve Griffiths

  • Light and Dark Reactions in Photosynthesis ..

    Light-independent reactions - Wikipedia

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Photosynthetic: Light reactions/Dark reactions | New …

The Dark reaction – Calvin Cycle
The dark reaction is also called the light-independent reaction or the Calvin Cycle. It occurs in the stroma of chloroplasts of plant cells. These processes do not use light (hence dark reaction). Carbon dioxide is combined with the energy produced in the light reaction t make sugars for plant growth and energy.

10 thoughts on “ Photosynthetic: Light reactions/Dark reactions ”

Photosynthesis is a process where by energy from light is harvested and used to drive synthesis of organic carbohydrates from carbon dioxide and water. Photosynthesis takes place in chloroplasts and can be divided into two steps: light reactions which require light and dark reactions which do not require light. During light reaction, light energy is captured by photosystems and electrons are transferred among the electron receptors. ATP and NADPH are generated. During dark reactions, CO2 is fixed using ATP and NADPH generated by the light reactions and organic carbohydrates are synthesized via the Calvin Cycle. When the CO2 is first fixed into a 3 carbon compound 3PGA, it is called C3 pathways and these plants are called C3 plants. The disadvantage of C3 plants is that they undergo photorespiration and thus waste some energy gained in light reactions. C4 cycle is the pathway adopted by C4 plants to bypass photorespiration.

Difference between Light and Dark Reactions in Photosynthesis ..

These electrons are passed through proteins in the thykaloid membrane as part of what is called the electron transport process, and are eventually attached to NADP+ (nicotine adenine dinucleotide phosphate) and H+ to form NADPH, another energy carrier needed in the dark reactions phase.

The Dark Reactions of Photosynthesis - Halley hosting

The hydrogen ions haven't been used up, so they can next be used to make the NADPH and H+ needed in the dark reactions, or can be pumped back into the confined space by the proton pump to power the production of more ATP.

In the Light-Independent Process (the Dark reaction) ..

The Light Reaction
Pigments in photosystem II absorb light. The light excites electrons, energizing
them. The high-energy electrons move to photosystem I and get re-energized. The electrons’ energy is harvested to pump H+ ions from the stroma into the thylakoids. NADP+ picks up some of the H+ and electrons to become NADPH. The leftover H+ diffuse back out to the stroma, passing through ATP synthase. ATP synthase produces ATP.

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