Competitive Exams: Botany MCQs (Practice-Test 93 of 104)

  1. Nucleosome is an ellipsoidal bead-like structure with a length of 110 A ‘and a diameter of 65 to 75 A’ Its core consists of an octamer of his tones and its surface is surrounded by a super-helical strand of DNA of about

    1. 110 base pairs

    2. 140 base pairs

    3. 210 base pairs

    4. 265 base pairs

  2. The plastids which are filled with a large amount of lipids are called

    1. Etiolates

    2. Elastoplasts

    3. Leucoplasts

    4. Amyloplasts

  3. Some cellular structures are bound by single or double membranes while some others are without a membrane. Match the organdies in List I with the nature of membranes in List II and select the correct answer using the codes given below the lists:

    List-I List-II
    1. Mitochoridria

    2. Lysosornes

    3. Rlbosomes

    4. Nucleus

    1. Without membrane

    2. Single membrane

    3. Double membrane

    • A
    • B
    • C
    • D
      • 1
      • 2
      • 3
      • 2
      • 3
      • 1
      • 2
      • 1
      • 3
      • 2
      • 1
      • 3
      • 2
      • 3
      • 1
      • 3
  4. Is chromosomes are formed by

    1. Pairing of identical chromosomes

    2. Longitudinal splitting of Centro mere

    3. Transverse division of Centro mere

    4. Disjunction of bivalents

  5. The formation of multivalent at meiosis in a diploid organism is due to

    1. Inversion

    2. Deletion

    3. Monosomy

    4. Reciprocal translocation

  6. Which one of the following is known to act as a biological mutagen?

    1. Acridine orange

    2. Nitrosoguanidine

    3. Transposon

    4. Streptomycin

  7. Match List I with List II and select the correct answer using the codes given below the lists:

    List-I List-II
    1. Autotetraploid

    2. Ac-Ds system

    3. Segmental allopolyploid

    4. Genetic Cinderella

    1. Triticum aestivum

    2. Drosophila melanogaster

    3. Secale cereale

    4. Zea mays

    • A
    • B
    • C
    • D
      • 3
      • 4
      • 1
      • 2
      • 2
      • 1
      • 4
      • 3
      • 3
      • 1
      • 4
      • 2
      • 2
      • 4
      • 1
      • 3
  8. Gene dosage depends upon the

    1. Total number of genes

    2. Ploidy level of the species

    3. Frequency of induced mutations

    4. Number of chromosomes involved in reciprocal translocations

  9. Match List I with List II and select the correct answer using the codes given below the lists:

    List-I List-II
    1. Failure of spindle to organize

    2. Dissolution of cell wall

    3. Fusion of plant protoplasts

    4. Induction of mutation

    1. Nitrous acid

    2. Cellulase

    3. Coichicine

    4. PEG

    • A
    • B
    • C
    • D
      • 3
      • 2
      • 4
      • 1
      • 3
      • 2
      • 1
      • 4
      • 2
      • 3
      • 4
      • 1
      • 2
      • 3
      • 1
      • 4
  10. When a pyramiding base is replaced by a purine or vice-versa in the DNA polynucleotide chain, the process is known as

    1. Transmutation

    2. Tran version

    3. Translocation

    4. Transfect ion

  11. Two genes a and b present on the same chromosome show 12% recombination. The distance between them is

    1. 0.12 map units

    2. 1.2 map units

    3. 12 map units

    4. 120 map units

  12. RFLP (Restriction Fragment Length Polymorphism) study is a technique for

    1. Transferring genes from unrelated species

    2. Isolating single genes

    3. Isolating single genes products

    4. Identifying genetic (DNA) homologies

  13. Consider the following statements regarding linkage:

    1. The linked genes are located on the same chromosome.

    2. Crossing over between linked genes is rare.

    3. Linked genes are always inherited together.

    4. Linkage affects the percentage of homozygosis following hybridization.

    Of these statements

    1. 1 and 3 are correct

    2. 1 and 2 are correct

    3. 2, 3 and 4 are correct

    4. 1, 3 and 4 are correct

  14. He erotic effect in a hybrid is due to

    1. Over dominance at most loci

    2. Non-allelic interaction

    3. Inter-allelic interaction

    4. Additive genes effects

  15. Expression of a recessive phenotype in a deletion heterozygote is due to

    1. Pseudo-dominance

    2. Partial-dominance

    3. Super-dominance

    4. Co-dominance