Competitive Exams: Botany MCQs (Practice-Test 60 of 104)

  1. Very small organisms like bacteria encode much more information than the number of triplets they have. This suggests that

    1. The genetic code is overlapping

    2. Genes are non-overlapping

    3. Each base pair codes for one amino acid

    4. Genetic code is non-overlapping but the genes are overlapping

  2. Match List I with List II and select the correct answer

    List-I List-II
    1. Operator gene

    2. Promoter gene

    3. Regulator gene

    4. Structural gene

    1. Provides a site for binding of activator proteins and RNA polymerase

    2. Makes enzymes that control metabolism such as lactose in the cell

    3. Switches on citron activity

    4. Synthesizes a molecule that blocks a gene adjacent to structural genes

    • A
    • B
    • C
    • D
      • 2
      • 1
      • 3
      • 4
      • 3
      • 1
      • 4
      • 2
      • 2
      • 3
      • 4
      • 1
      • 3
      • 4
      • 1
      • 2
  3. Mendel Ian genetics is described as ‘forward genetics’ as against the recently coined phrase ‘reverse genetics’ Reverse genetics refers to those cases where

    1. Proteins can be used to obtain RNA

    2. Reverse transcription is involved

    3. Central dogma is reversed

    4. The gene products is unknown

  4. If an individual with genotype a1 +/+ a2 has a wild phenotype then it would mean that a1 and a2

    1. Belong to different citrons

    2. Belong to the same citron

    3. Belong to the same mutton

    4. Do not complement

  5. In human beings, sex determination has recently been studied in great details using techniques of mo0lecular biology. The most important gene located on Y chromosome and involved in sex determinations is

    1. SRY gene

    2. Sx 1 gene

    3. ZFY gene

    4. tra gene

  6. Which one of the following pairs of plant diseases and symptoms is correctly matched?

      • Rice infected with Helminthosporium Oryzae
      • Blight
      • Jute infected with Macrphoming Phaseolina
      • Club root
      • Crucifer infected with Plasmodiophora Brassicae
      • Rot
      • Potato infected with Synchytrium
      • Endobioticum wart
  7. Consider the following events:

    1. Germ tube formation

    2. Aspersoria formation

    3. Penetration

    4. Haustoria's formation

    The correct sequence in which these events take place during plant infection is

    1. 2, 1, 4, 3

    2. 2, 3, 1, 4

    3. 1, 2, 3, 4

    4. 1, 2, 4, 3

  8. Primary inoculums of red rot of sugarcane comes from

    1. Mycelium in reddened pith

    2. Conidia and mycelium in buds

    3. Acervuli in the rind

    4. Conidia and mycelium in debris

  9. Substances which are formed by host tissue in response to injury, physiological stimuli, infectious agents or their products which inhibit the growth of microorganisms are called

    1. Phytotoxins

    2. Phytoalexins

    3. Inhibitions

    4. Prohibitions

  10. Bacillus thuringiensis is used to control

    1. Bacterial pathogens

    2. Fungal patliogens

    3. Nematodes

    4. Insect pests

  11. Crown gall symptoms are present in

    1. Peas, apple and sugarcane

    2. Pear, grapes and sugarcane

    3. Apple, grapes and sugarcane

    4. Pear, apple and grapes

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

    List-I (Food items) List-II (Plant sources)
    1. Mustard

    2. Groundnut

    3. Pigeon pea

    4. Gram

    1. Arachis hypogea

    2. Cicer arietinum

    3. Cajanus cajan

    4. Brassica juncea

    • A
    • B
    • C
    • D
      • 4
      • 2
      • 3
      • 1
      • 4
      • 3
      • 2
      • 1
      • 1
      • 4
      • 3
      • 2
      • 4
      • 1
      • 3
      • 2
  13. Match List I with List II and select the correct answer:

    List-I List-II
    1. Wind

    2. Soil

    3. Seed

    4. Aphid

    1. Bunchy top of banana

    2. Wheat rust

    3. Cabbage club rot

    4. Tomato fruit canker

    5. Tobacco mosaic

    • A
    • B
    • C
    • D
      • 1
      • 2
      • 4
      • 5
      • 2
      • 3
      • 5
      • 1
      • 3
      • 2
      • 5
      • 4
      • 2
      • 3
      • 4
      • 1
  14. The staple crop in Ireland was completely destroyed in 1844 − 1846, by a fungal disease resulting in a great famine. The causal organism in this case was

    1. Puccinia graininis

    2. Ustilago tritici

    3. Phytophthora infestans

    4. Claviceps purpurea

  15. Which one of the following combinations of microbes is responsible for the formation and flavor of Yoghurt?

    1. Lactobacillus casei and Streptococcus thermopiles

    2. Rhizobium maillot and Azotobacter species

    3. Ebodoiquerillurs rub urn and Scincealla typhosa

    4. Bacillus subtitles and Escherichia coli