Tag: modern concept of photosynthesis
Questions Related to modern concept of photosynthesis
In photosynthesis, splitting of water occurs during
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Cyclic photophosphorylation
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Non-cyclic photophosphorylation
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Oxidative photophosphorylation
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Calvin cycle
Photolysis of a water molecule yields
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2 electrons and 4 protons
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4 electrons and 4 protons
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4 electrons and 2 protons
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2 electrons and 2 protons
Photolysis is part of the light-dependent reactions of photosynthesis. The general reaction of photosynthetic photolysis can be given as
H2AH2A + 2 photons (light) → 2 e−e− + 2 H+H+ + A
So, the correct option is 'Option D'.
Minerals involved in photolysis are
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Mg and CI
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K and Mn
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Mo and Mn
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Mn and Cl
A) Mg is responsible for the activation of many enzymes, but is not involved in photolysis. Cl ions help in the photolysis of water.
Extrusion of electron from reaction centre of PS II leaves a hole which is filled by electron released from
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$H _2O$
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$CO _2$
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Chlorophyll
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Light
Non-cyclic phosphorylation involves both Photosystem I and Photosystem II. These two photosystems work in series, first PS II and then PS I. The two photosystems are connected through an electron transport chain. $NADPH$ is synthesized by this kind of electron flow. Electrons are transferred from the PS II and then passed on to the pigments of PS I. Then, electrons get excited and transferred to another acceptor. These electrons are then moved downhill again to a molecule of $NADP^{+}$. The addition of these electrons results in the formation of $NADPH$. Extrusion of the electron from reaction centre of PS II leaves a hole which is filled by electron released from $H _{2}O$. This is achieved by electrons available due to the splitting of water. The water splitting complex is associated with PS II, which itself is physically located on the inner side of the membrane of the thylakoid. Water is split into $H^{+}$, $O$ and electrons. The protons and oxygen formed by splitting of water is released within the lumen of the thylakoids. The oxygen produced is released as one of the net products of photosynthesis.
Isotope of oxygen used in studying photolysis is
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$^{16}O$
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$^{15}O$
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$^{17}O$
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$^{18}O$
A) $ _{ \quad }^{ 16 }{ O }$ is not used to study photolysis.
B) $ _{ \quad }^{ 15 }{ O }$ is not used to study photolysis.
So the correct answer is '$ _{ \quad }^{ 18 }{ O }$'.
Mineral involved in photolysis of water are
(a) Mn
(b) Ca
(c) Mg
(d) Cl
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a, b
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a, b, d
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c, d
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a, b, c
A) Mn and Ca are involved in the photolysis of water.
B) Mn, Cl and Ca are involved in the photolysis of water.
D) Mn and Ca are involved in the photolysis of water. but Mg is not involved.
So the correct answer is 'a, b, d'.
Mn, Ca and Cl present in PS II play an important role in
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Absorption of light
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$CO _2$ assimilation
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Photolysis of water
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ATP synthesis
A) Absorption of light is carried out by photosynthetic pigments.
D) PS I and PS II are involved in ATP synthesis
So, the correct answer is 'Photolysis of water'
The essential element required for water splitting in photosynthesis leading to release of oxygen is
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Mo
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Mn
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Mg
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K
During ATP synthesis in the chloroplast, the proton gradient is formed. There are several processes that take place during activation of electrons and their transport which lead to the development of a proton gradient. Photolysis of water is the first process of this activation. The splitting of the water molecule takes place on the inner side of the thylakoid membrane and so the hydrogen ions (protons) that are produced, they accumulate within the lumen of the thylakoids. Oxygen-evolving complex called Z-enzyme is attached to the inner surface of the thylakoid membrane. The enzyme has four Mn ions. Light energized Mn and removes electrons from $OH^{-}$ component of water forming oxygen. So, the essential element required for water splitting in photosynthesis leading to release of oxygen is Mn.
State whether the following statements are true or false
The ultimate electron donor in photosynthesis is water
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True
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False
In oxygenic photosynthesis, the first electron donor is water, creating oxygen as a waste product. In anoxygenic photosynthesis, various electron donors are used. Cytochrome b6f and ATP synthase work together to create ATP. This process is called photophosphorylation.
Which statements is correct for given reaction for photosynthesis:-
${ 2H } _{ 2 }A+C{ O } _{ 2 }\underrightarrow { light } 2A+{ C }H _{ 2 }O+{ H } _{ 2 }O$
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H donor from ${ H } _{ 2 }O$ if reducible compound is ${ H } _{ 2 }O$
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${ O } _{ 2 }$ evolve from ${ H } _{ 2 }O$ if a reducible compound is${ H } _{ 2 }O$
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Glucose gain its oxygen from ${ H } _{ 2 }O$
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$(1)$ & $(3)$ both
The oxygen evolution is part of the light-dependent reactions of photosynthesis in cyanobacteria and the chloroplasts of green algae and plants. It utilizes the energy of light to split a water molecule into its protons and electrons for photosynthesis. Free oxygen, generated as a by-product of this reaction, is released into the atmosphere.