Competitive Exams: Botany MCQs (Practice-Test 16 of 104)

  1. Legume root nodules contain leg hemoglobin. Its function is to regulate

    1. Expression of nif genes

    2. Dinitrogenase activity

    3. Oxygen supply

    4. Nodule growth

  2. Dinitrophenol inhibits cell function by disrupting

    1. Citric acid cycle

    2. Oxidative phosphroylation

    3. Glycol sis

    4. Gluconeogenesis

  3. Which one of the following mineral elements does NOT appear to be structurally bound in plants?

    1. Nitrogen

    2. Calcium

    3. Phosphorus

    4. Potassium

  4. Match List I (Element) with List II (Process) and select the correct answer:

    List-I List-II
    1. Molybdenum

    2. Managanese

    3. Sulphur

    4. Calcium

    1. Photosynthesis

    2. Respiration

    3. Nitrate reduction

    4. Cell division

    5. Protein synthesis

    • A
    • B
    • C
    • D
      • 5
      • 2
      • 3
      • 1
      • 3
      • 1
      • 5
      • 4
      • 2
      • 1
      • 4
      • 5
      • 3
      • 2
      • 4
      • 5
  5. Urease is an enzyme that catalyses the hydrolysis of urea into NH3 and CO2. The metallic cofactor of the enzyme is

    1. Ni

    2. Fe

    3. Mn

    4. Cu

  6. Some antibiotics act ionospheres, which means that they

    1. Interfere directly with bacterial cell well synthesis

    2. Increase cell membrane permeability to specific ions

    3. Inhibit both transcription and translation

    4. Inhibit electrophoresis separation of ions

  7. The disease little leaf of fruit trees is caused by the deficiency of

    1. Copper

    2. Zinc

    3. Manganese

    4. Cobalt

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

    List-I List-II
    1. Field capacity

    2. Permanent wilting

    3. Water deficit

    4. Soil moisture tension

    1. Forces which hold water to the soil

    2. Combine effect of accelerated water loss and retarded water absorption

    3. Water content of a soil

    4. Loss of water from plant with little chance of regaining turgidity

    • A
    • B
    • C
    • D
      • 3
      • 4
      • 2
      • 1
      • 1
      • 2
      • 3
      • 4
      • 2
      • 4
      • 3
      • 1
      • 3
      • 1
      • 2
      • 4
  9. Which one of the following alterations in DNA is likely to be lethal?

    1. Substitution of adenine for cytosine

    2. Substitution of methyl cytosine for cytosine

    3. Deletion of thee nucleotides

    4. Insertion of one nucleotide

  10. Which one of the following statements about ribosome's is correct?

    1. They are an integral part of transcription

    2. They are found both free in the cytoplasm and bound to membranes

    3. They are composed of RNA, DNA and protein

    4. They are bound so tightly that they cannot dissociate under physiological conditions

  11. An increased melting temperature for duplex DNA results from a high content of

    1. Adenine + guanine

    2. Cytosine + thymine

    3. Cytosine + guanine

    4. Adenine + cytosine

  12. The post-translational processing of secretary proteins takes place in

    1. Plastids

    2. Golgi bodies

    3. Mitochondria

    4. Nucleus

  13. The brief addition of a radioactive compound to the sample reaction mixture followed by its removal and its replacement by an excess of unlabelled compound during the study of a biosynthetic pathway is called

    1. Autoradiography

    2. Molecular hybridization

    3. Pulse-chase experiment

    4. Partial sequence analysis

  14. Florigen is considered to be a combination of

    1. Gibberellin and cytokinin

    2. Gibberellin and anthesin

    3. Cytokinnin and abscisic acid

    4. Cytokinin and anthesin

  15. Organs such as stolons and rhizomes, which grow at right angles to the pull of gravity are called to be

    1. Plagiogravitropic

    2. Diagravitropic

    3. Agravitropic

    4. Semigravitropic