Biology today

(Grace) #1

  1. The given figure is a schematic
    break-up of the phases/stages
    of cell cycle. Which one of the
    following is the correct indication of
    the stage/phase in the cell cycle?
    (a) C - karyokinesis
    (b) D - synthetic phase
    (c) a - cytokinesis
    (d) b - metaphase

  2. When synapsis is complete the cell is said to have entered a
    stage called
    (a) zygotene (b) pachytene
    (c) diplotene (d) diakinesis.

  3. Crossing over occurs in
    (a) non-sister chromatids of homologous chromosome at
    two stranded stage
    (b) non-sister chromatids of homologous chromosome at
    four stranded stage
    (c) sister chromatids of homologous chromosome at two
    stranded stage
    (d) sister chromatids of homologous chromosome at four
    stranded stage.

  4. If a cell contains 36 chromosomes, what will be the number
    of chromosomes in each of the 4 daughter cells resulting
    from meiosis?
    (a) 36 (b) 18
    (c) 9 (d) none of these

  5. The number of mitotic cell division required to produce 256
    cells from single cell would be
    (a) 10 (b) 12
    (c) 6 (d) 8

  6. During which stage of meiosis, synaptonemal complex is
    formed?
    (a) Pachytene (b) Diplotene
    (c) Diakinesis (d) Zygotene

  7. Chiasmata formation takes place during
    (a) prophase I (b) metaphase I
    (c) anaphase II (d) telophase I.

  8. During meiosis I, the bivalent chromosomes clearly appear
    as tetrads during
    (a) diakinesis (b) diplotene
    (c) leptotene (d) pachytene.

  9. Select the correct option with respect to mitosis.
    (a) Chromatids separate but remain in the centre of the cell
    in anaphase.
    (b) Chromatids start moving towards opposite poles in
    telophase.
    (c) Golgi complex and endoplasmic reticulum are still visible
    at the end of prophase.
    (d) Chromosomes move to the spindle equator and get
    aligned along equatorial plate in metaphase.
    16. Select the correct match.
    (a) S phase – DNa replication
    (b) Zygotene – Synapsis
    (C) Diplotene – Crossing over
    (D) Meiosis – both haploid and diploid cells
    (e) Gap-2 phase – Quiescent stage
    (a) a and b (b) C and D
    (c) C and e (d) a, C and e
    17. find the correctly matched pairs and choose the correct
    option.
    a. Leptotene – The chromosomes become
    invisible
    b. Zygotene – Pairing of homologous
    chromosomes
    C. Pachytene – Dissolution of the synaptonemal
    complex takes place
    D. Diplotene – bivalent chromosomes appear as
    tetrads
    e. Diakinesis – Terminalisation of chiasmata takes
    place
    (a) a and b are correct. (b) b and D are correct.
    (c) b and e are correct. (d) b and C are correct.
    18. Which of the following events are not characteristic features
    of telophase?
    a. Chromosome material condenses to form compact
    mitotic chromosomes.
    b. Nucleolus, Golgi complex and er reform.
    C. Nuclear envelope assembles around the chromosome
    clusters.
    D. Centromeres split and chromatids separate.
    e. Chromosomes cluster at opposite, spindle poles and
    their identity as discrete elements is lost.
    (a) a, b and D only (b) a and D only
    (c) b and C only (d) C, D and e only
    19. a stage in mitosis that starts towards the middle of anaphase
    and is completed with the telophase is
    (a) cytokinesis (b) karyokinesis
    (c) crossing over (d) interkinesis.
    20. Which of the following statements is incorrect about G 0
    phase?
    (a) Mitosis occurs after G 0 phase.
    (b) biocatalysts can be used to exit G 0 phase.
    (c) Cell volume keeps on increasing during this phase.
    (d) Cell metabolism occurs continuously in G 0 phase.


ANSWER KEY



  1. (d) 2. (d) 3. (d) 4. (a) 5. (a)

  2. (a) 7. (b) 8. (b) 9. (b) 10. (b)

  3. (d) 12. (d) 13. (a) 14. (d) 15. (d)

  4. (a) 17. (c) 18. (b) 19. (a) 20. (a)
    

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