CSIR NET JRF: Botany MCQs (Practice-Test 27 of 104)

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1. In simple osmotic systems, at-constant temperatures, the water potential results from the combined but opposite actions of

   1. Relative humidity and pressure potential

   2. Pressure potential and saturation vapour potential

   3. Saturation vapour pressure and osmotic potential

   4. Osmotic potential and pressure potential

2. In the presence of a competitive inhibitor, the relation between the rate of enzyme reaction and substrate concentration is modified so that there is

   1. Increase in Km but no change in Vmax

   2. Increase in Km but decrease in Vmax

   3. Increase in Vmax but no change in Km

   4. Increase in Vmax but decrease in Km

3. The idea that pH gradients could provide energy for ATP formation in chloroplasts and mitochondria was first proposed by

   1. Bassham

   2. Hill

   3. Mitchell

   4. Thompson

4. Match List I (Compound oxidized during Krebs cycle) with List II (Compound formed on oxidation) and select the correct answer

   List-I	List-II
   Pyruvic acid Isocitric acid a-Ketoglutaric acid Succinic acid	AcetylCoA Succinyl CoA Oxaloacetic acid Oxalosccinic acid Fumaric acid

   • A
   • B
   • C
   • D
   1. • 1
      • 4
      • 3
      • 2
   2. • 2
      • 1
      • 3
      • 4
   3. • 3
      • 1
      • 2
      • 5
   4. • 1
      • 4
      • 2
      • 5

5. Which one of the following processes accounts for the accumulation of some ions inside the vacuole of the cell at a higher concentration than in the surrounding medium?

   1. Diffusion

   2. Donnan equilibrium

   3. Energy dependant uptake

   4. Osmosis

6. Level of Zn controls the normal auxin context through its effect on the synthesis of

   1. Tiyptophan

   2. Methionjne

   3. Glutamic acid

   4. IAA oxidase

7. Which one of the following is a good chelating agent used for converting iron into absorbable form by plants growing in nutrient solutions?

   1. Dinitrophenol

   2. Diphenylcaybazide

   3. Ethylenediarmine tetraacetic acid

   4. Para-aminobenzoic acid

8. The number of ribosomal binding sites used by tRNAs during protein elongation are

   1. 2

   2. 4

   3. 6

   4. 8

9. Consider the following statements: A factor called ‘sigma factor’ is involved in the transcription process during protein synthesis. This factor

   1. interacts with the core enzyme RNApolymerase and forms the complete active enzyme

   2. Recognizes the start signal on DNA and directs the binding of the enzyme to the promoter region

   3. Along with the RNA factor helps RNA to dissociate from RNA-polymerase and thus helps to terminate transcription

   Which of these statements are correct?

   1. 1 and 2

   2. 1 and 3

   3. 2 and 3

   4. 1, 2 and 3

10. Zea mays is a

    1. Day-neutral plant

    2. Long-day plant

    3. Short-day plant

    4. Long-short-day plant

11. In the studies of photosynthetic pathways after the chromatographic separation of radioactively labeled sugars, they could be detected by placing the paper chromatogram in contact with a sheet of X-ray film. This technique is called

    1. Autoradiography

    2. Chromatography

    3. Reverse-flap technique

    4. Spectrophotometer

12. Match List I with List II and select the correct answer:

    List-I (Plant)	List-II
    Cassava Clusterbean Radish. Turnip	Brassica rapa Cyamopsis tetragonoloba Manihot esculena Raphanus sativus

    • A
    • B
    • C
    • D
    1. • 1
       • 2
       • 4
       • 3
    2. • 3
       • 2
       • 4
       • 1
    3. • 1
       • 4
       • 2
       • 3
    4. • 3
       • 4
       • 2
       • 1

13. With reference to Zea mays, consider the following embryonic tissues

    1. Pericarp

    2. Endosperm

    3. Aleurone

    Which of these structures is/are triploid?

    1. 1, 2 and 3

    2. 2 only

    3. 1 and 3

    4. 2 and 3

14. In some flowering plants, the requirement of long day length or low temperature treatment for flowering can be effectively substituted by

    1. Morphactins

    2. Coumarins

    3. 2, 4 − D

    4. Gibberellins

15. Under water stress, plants increase the synthesis of

    1. Gibberellic acid

    2. Cytokinin

    3. Auxins

    4. Abscisic acid