Multiple Choice Questions

Advertisement

Photorespiration shows formation of

  • sugar but not ATP

  • ATP but not sugar

  • both ATP and sugar

  • neither ATP nor sugar


D.

neither ATP nor sugar

Photorespiration is the light dependent process of oxygenation of ribulose biphosphate (RuBP) and release of carbon dioxide by the photosynthetic organs of a plant. Normally photosynthetic organs do the reverse in the light, i.e., uptake of CO2 and release of O2 At high temperature, RuBP carboxylase functions as oxygenase and instead of fixing carbon dioxide (C4 cycle), oxidises ribulose 1, 5-biphosphate to produce a 3-carbon phosphoglyceric acid and a 2-carbon phosphoglycolate. Photorespiration does not produce energy or reducing power. Rather, it consumes energy. Further, it undoes the work of photosynthesis. There is 25% loss of fixed CO2. Therefore, photorespiration is a highly wasteful process. This happens only in case of C4 plants. C4 plants have overcome the problem of photorespiration.


Advertisement

Cyclic photophosphorylation involves

  • PS I

  • PS II

  • PS I and PS II

  • P680


The first stable product of Calvin cycle is

  • 3- phosphoglycerate

  • 1, 3 biphosphoglycerate

  • glyceralydehyde - 3 phosphate

  • ribulose - 5 - phosphate


C4 plants have better productivity because

  • C4 plants absorb more light

  • C4 plants absorb more CO2

  • C4 plants does not carry photorespiration

  • C4 plants have more amount of RuBisCO


Assertion : Due to pollution atmospheric concentration of CO2 is increasing which will be harmful for C4 plants whereas productivity is going to increase for C3 plants.

Reason : C4 plants have greater efficiency for CO2 as CO2 is fixed by PEP oxygenase.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


Advertisement

Assertion : The efficiency of C4 plant is more than those of C3 plant.

Reason : C4 plants are more efficient in picking CO2.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are hue but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


Assertion: Photorespiration interferes with the successful functioning of Calvin cycle.

Reason: Photorespiration oxidises ribulose1,5 biphosphate which is an acceptor of CO2 in Calvin cycle.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


PS-II occurs only in

  • stroma

  • granal thylakoids

  • stromal lamella

  • matrix


Which of the following is correctly labelled for the given figure

  • A: PS II; B : PS I; C :e- acceptor, D: LHC

  • A: LHC; B:e- acceptor; C: PS I; D: PS II

  • A: PS I; B:PS II; C:e- acceptor; D: LHC

  • A: e- acceptor; B : LHC; C: PS Il; D: PS I


Advertisement
<

Kranz anatomy is usually associated with

  • C3 plants

  • C4 plants

  • CAM plants

  • C3-C4intermediate plants.


Advertisement