Multiple Choice Questions

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During photosynthetic carbon reduction cycle in green leaves, net production of one molecule of glyceraldehyde 3-phosphate requires one of the following combinations of energy equivalents:

  • 9 NADPH and 6 ATP

  • 3 NADPH and 9 ATP

  • 2 NADPH and 3 ATP

  • 6 NADPH and 9 ATP


D.

6 NADPH and 9 ATP

During photosynthetic carbon reduction cycle in green leaves, the net production of one molecule of glyceraldehyde 3-phosphate requires 6 NADPH and 9 ATP molecules.

ATP and NADPH are used to convert the six molecules of phosphoglyceric acid (3-PGA) into six molecules of a chemical called glyceraldehyde 3-phosphate (G3P). 


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Following are some facts regarding localization of photosynthetic supramolecular complexes on plastid lamellae:

(A) PSII is preferentially located on grana lamellae.

(B) ATP synthase and PSI are preferentially located on stromal lamellae.

(C) PSI and PSII are located adjacent to each other on stromal lamellae.

(D) Cyt b6/f complex is not a membrane-bound complex.

Which one of the following combinations of the statement is true?

  • (A) and (B)  

  • (C) and (D)

  • (B) and (D)

  • (B) and (C)


Which of the following is NOT an adaptive modification in a xerophytic plant?

  • Strongly developed sclerenchyma

  • Sunken stomata

  • Sparse stomata

  • Presence of lacunar tissues   


Red and far-red lights are perceived by plants through various photoreceptors including phytochromes. The activation of phytochrome is caused by:

  • Conversion of Pr to Pfr from through the effect of red light.  

  • Repression of Pr form through the effect of far-red light.

  • Equal proportion of red and far-red lights at the same fluence rates.

  • Presence of red and far-red light at different fluence rates.


Phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) are involved in the biosynthesis of phenolic compounds in plants. The following are some statements regarding the actions of PAL and CHS.

(A) Substrates for PAL and CHS are phenylalanine and chalcone respectively.

(B) PAL converts phenylalanine to trans-cinnamic acid.

(C) PAL converts phenylalanine to p-coumaric acid.

(D) p-coumaroyl-CoA is converted to chalcones by CHS.      

Which one of the following combinations of the above statements is true?

  • (A) and (B)

  • (A) and (C)

  • (B) and (C)

  • (B) and (D)


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The following are certain facts about the effect of abscisic acid (ABA) on the development and physiology effect of the plant.

(A) ABA promotes lead senescence independent of ethylene.

(B) ABApromotes shoot growth and inhibits root growth at low water potentials.

(C) ABA inhibits gibberellin induced enzyme production.

(D) Seed dormancy is controlled by the ratio of ABA and gibberellins.

Which one of the following combinations of the above statements is true?

  • (A), (B), and (C)

  • (B), (C), and (D)

  • (A), (B), and (D)

  • (A), (C), and (D)


Which one of the following statements is INCORRECT about the role of oxidative pentose phosphate pathway in plant metabolism?

  • Generation of NADPH required to drive biosynthetic reactions.

  • Production of pentose phosphate for the synthesis of nucleic acids.

  • Formation of erythrose 4-phosphate for biosynthesis of aromatic amino acids.

  • Production of NADH to generate ATP


Which one of the following combinations of secondary metabolite biosynthetic pathways results in the biosynthesis of terpenes?

  • Mevalonic acid and MEP pathways.  

  • Malonic acid and MEP pathways.

  • Shikimic acid and malonic acid pathways.

  • Shikimic acid and Mevalonic acid pathways.


Symbiotic biological nitrogen fixation takes place with the association between a plant and a nitrogen-fixing prokaryote as shown in the following table:

List of plants Nitrogen-fixing
A. Soybean (i) Frankia
B. Casuarina (ii) Bradyrhizobium
C. Gunnera (iv) Anabaena
D. Azolla (v) Nostoc

The correct combination is:

  • A – i; B – ii; C – iii; D – iv

  • A – ii; B – i; C – iv; D – iii     

  • A – iii; B – ii; C – i; D – iv

  • A – iv; B – iii; C – ii; D – i


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While studying the primary effects of different abiotic stresses on plants, a researcher observed water potential (φp) reduction and cellular dehydrations. Which of the following combination of abiotic stresses may cause the observed effect?

  • Water deficit, salinity, and chilling.

  • Salinity, high-temperature, and flooding.

  • Freezing, salinity and water deficit.      

  • Freezing, chilling, and flooding.


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