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Excitation of chlorophyll by light is

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Important Questions on Photosynthesis

EASY
No. of ATP, O2 molecules and NADPH released in photophosphorylation when 12H2O molecules undergo photolysis
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Which of the following are required for chemiosmosis?

I. A membrane

I. A neutron pump

II. An electron gradient

IV. ATPase

The correct answer is:

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Assertion A: During photophosphorylation protons are transported across the membrane and accumulated inside the lumen.

Reason R: To develop proton gradient, pheophytin transfers electrons to hydrogen carriers instead of electron carrier.

EASY
Proton motive force is created by pumping protons across the
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The graph below represents the absorption spectrum of a major pigment contributing to photosynthesis.

Question Image
Which one of the following best represents the photosynthetic efficiency of the pigment?

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Arrange the given reactions occur in electron transport in correct sequence.

I) Oxygen Removes H2 from ETS Receives electrons form ETS.

II) Ubiquinone Oxidized from ubiquinol Receives reduced equivalents from FADH2.

III Cyt C oxidase Reduced by cytochrome C Electron donor for O2 to release H2O.

IV) Cytochrome C Mobile carrier Transfer e- from cyt b to cyt c oxidase.

EASY
Which of the following is/are the product(s) of cyclic photophosphorylation?
EASY
The deficiency of which of these elements interrupts photolysis of water during photosynthesis?
HARD

Arrange the path of electrons from water to the phycocyanin in the light reaction.

i) Plastoquinone

ii) Excited P680*

iii) Cyt f

iv) Fe-S

v) Pheophytin

vi) Quinone

The correct sequence is

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Non-cyclic photophosphorylation does NOT occur in _______.
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The oxygen evolved during photosynthesis comes from water molecules. Which one of the following pairs of elements is involved in this reaction?
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Which of the following is not a product of a light reaction of photosynthesis?
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Assertion (A): In PS I, the reaction centre, chlorophyll 'a' has an absorption peak at 700 nm, hence is called P700, while in PS II, it has absorption maxima at 680 nm and is called P680.

Reason (R): Calvin pathways occur in all photosynthetic plants, it does not matter where they have C3 or C4 pathways and the Calvin cycle described in three stages: Carboxylation, reduction and regeneration.

The correct answer is:

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In light reaction, plastoquinone facilitates the transfer of electrons from
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Emerson's enhancement effect and red drop have been instrumental in the discovery of:
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Which one of the following is due energy currency of the cell or The common immediate source of energy in cellular activity is
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Discovery of Emerson effect has clearly shown the existence of
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In noncyclic photophosphorylation, the pigment molecule first excited is
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Which one of the following elements is required for photosynthetic oxygen evolution