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Electron Transfer Pathway from Water to NADP in photosynthesis

Water is split in the process, and thus it is the light reactions of photosynthesis that give off 0, as a by-product.

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What is the role of NADP in photosynthesis - OpenStudy

Photosynthesis occurs inside chloroplasts. Chloroplasts contain chlorophyll, a green pigment found inside the thylakoid membranes. These chlorophyll molecules are arranged in groups called photosystems. There are two types of photosystems, Photosystem II and Photosystem I. When a chlorophyll molecule absorbs light, the energy from this light raises an electron within the chlorophyll molecule to a higher energy state. The chlorophyll molecule is then said to be photoactivated. Excited electron anywhere within the photosystem are then passed on from one chlorophyll molecule to the next until they reach a special chlorophyll molecule at the reaction centre of the photosystem. This special chlorophyll molecule then passes on the excited electron to a chain of electron carriers.

The reducing power is provided by NADPH, which acquired energized electrons in the light reactions.

Glycerate 3-phosphate is reduced during the reduction reactions to a three-carbon sugar called triose phosphate. Energy and hydrogen is needed for the reduction and these are supplied by ATP and NADPH + H+ (both produced during light-dependent reactions) respectively. Two triose phosphate molecules can then react together to form glucose phosphate. The condensation of many molecules of glucose phosphate forms starch which is the form of carbohydrate stored in plants. However, out of six triose phosphates produced during the reduction reactions, only one will be used to synthesise glucose phosphate. The five remaining triose phosphates will be used to regenerate RuBP.

the ATP and NADPH produce in the light reaction is long way process

Our next step toward understanding photosynthesis is to look more closely at how the two stages work, beginning with the light reactions.

Chapter 22 ("Electron Transport and Oxidative Phosphorylation") in Voet & Voet (3rd Edition) is one of the most important chapters in the entire text (at least in my opinion) and it would help to reread it as you look at the light reaction of photosynthesis in more detail over the next two lectures.

Photoaututrophs utilize sunlight for energy and CO2 for theircarbon source by this process of PHOTOSYNTHESIS whereby sunlightis absorbed by a complex compound known as chlorophyll andconverted to energy which drives a series of chemical reactionsthat ultimately removes hydrogen from water or other compoundsand then combines the hydrogen with carbon dioxide in a way thatproduces sugars.

what is NADP's role in photosynthesis? | Yahoo Answers

What two energy carrying molecules are produced by the light reactions of photosynthesis? ?

So we can summarize by saying that the photosynthetic plantstrap solar energy to form ATP and NADPH (Light Phase) and thenuse these as the energy source to make carbohydrates and otherbiomolecules from carbon dioxide and water (Dark Phase),simultaneously releasing oxygen in to the atmosphere. Thechemoheterotrophic animals reverse this process by using theoxygen to degrade the energy-rich organic products ofphotosynthesis to CO2 and water in order to generate ATP fortheir own synthesis of biomolecules.

So how can these factors have an effect on the rate of photosynthesis? Lets start off with the light intensity. When the light intensity is poor, there is a shortage of ATP and NADPH, as these are products from the light dependent reactions. Without these products the light independent reactions can't occur as glycerate 3-phosphate cannot be reduced. Therefore a shortage of these products will limit the rate of photosynthesis. When the carbon dioxide concentration is low, the amount of glycerate 3-phosphate produced is limited as carbon dioxide is needed for its production and therefore the rate of photosynthesis is affected. Finally, many enzymes are involved during the process of photosynthesis. At low temperatures these enzymes work slower. At high temperatures the enzymes no longer work effectively. This affects the rate of the reactions in the Calvin cycle and therefore the rate of photosynthesis will be affected.

How is the function of nad similar to that of nadp in photosynthesis? - 8279998
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  • Tt helps the reduction of carbon dioxide into glucose

    What is the role of NADP in photosynthesisNADP is a co enzyme which acts as a hydrogen carrier

  • NADP is reduced in the light reaction of photosythesis

    Reduced NADP is needed in the light-independent reactions of photosynthesis

  • Photosynthesis Quiz - Science Geek

    NADH is involved in respiration while NADPH is involved in photosynthesis.

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Chemistry for Biologists: Photosynthesis

In addition to producing NADPH, the light dependent reactions also produce oxygen as a waste product. When the special chlorophyll molecule at the reaction centre passes on the electrons to the chain of electron carriers, it becomes positively charged. With the aid of an enzyme at the reaction centre, water molecules within the thylakoid space are split. Oxygen and H+ ions are formed as a result and the electrons from the splitting of these water molecules are given to chlorophyll. The oxygen is then excreted as a waste product. This splitting of water molecules is called photolysis as it only occurs in the presence of light.

Nicotinamide adenine dinucleotide phosphate - …

If the light intensity is not a limiting factor, there will usually be a shortage of NADP+ as NADPH accumulates within the stroma (see light independent reaction). NADP+ is needed for the normal flow of electrons in the thylakoid membranes as it is the final electron acceptor. If NADP+ is not available then the normal flow of electrons is inhibited. However, there is an alternative pathway for ATP production in this case and it is called cyclic photophosphorylation. It begins with Photosystem I absorbing light and becoming photoactivated. The excited electrons from Photosystem I are then passed on to a chain of electron carriers between Photosystem I and II. These electrons travel along the chain of carriers back to Photosystem I and as they do so they cause the pumping of protons across the thylakoid membrane and therefore create a proton gradient. As explained previously, the protons move back across the thylakoid membrane through ATP synthase and as they do so, ATP is produced. Therefore, ATP can be produced even when there is a shortage of NADP+.

IB Biology Notes - 8.2 Photosynthesis

The light-independant reactions of photosynthesis occur in the stroma of the chloroplast and involve the conversion of carbon dioxide and other compounds into glucose. The light-independent reactions can be split into three stages, these are carbon fixation, the reduction reactions and finally the regeneration of ribulose bisphosphate. Collectively these stages are known as the Calvin Cycle.

Light-dependent reactions of photosynthesis - BioTopics

Chloroplasts have many shapes in different species but aregenerally fusiform shaped (and much larger than mitochondria) andhave many flattened membrane-surrounded vesicles called thylakoidswhich are arranged in stacks called grana. Thesethylakoid membranes contain all of the photosynthetic pigments ofthe chloroplast and all of the enzymes required for Light Phasereactions. The fluid in the stroma surrounding the thylakoidvesicles contains most of the enzymes for Dark phase reactions.

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