Cell Cycle and Cell Division Mock Test – Class 11 Biology

1. Cell loss suddenly increases in a tissue whose resting cells can divide when replacement is required. The most likely response is:

2. Control and treated meiocytes both complete synapsis and form visible recombination nodules during pachytene. In treated cells, recombinase is inactive. Which outcome is most directly expected?

3. Two treatments are applied to proliferating diploid cells.

Which interpretation best fits the complete evidence?

4. A diploid cell enters S phase with the condition . Immediately after completion of DNA replication, before any chromosome segregation, its condition is:

5. Arrange the following events from late anaphase through telophase.
P. Daughter chromosomes approach opposite poles.
Q. Chromosomes begin elongating and decondensing.
R. Nuclear envelopes form around the chromosome groups.
S. Nucleoli and organised endomembrane structures reappear.

6. Arrange the following chromosome relationships in their normal meiotic order.
P. Homologous chromosomes undergo synapsis.
Q. Bivalents align at the metaphase-I equator.
R. Homologues separate while sister centromeres remain intact.
S. Individual chromosomes align in haploid cells and later separate their sisters.

7. A cell begins distributing chromosomes before genome duplication has been completed. This observation most directly indicates:

8. A chemical permits normal chromosome segregation and daughter-nucleus formation but prevents division of the cytoplasm. The most immediate expected outcome is:

9. Three curves record one cell lineage through a complete cycle. Cell mass rises gradually during interphase, DNA per cell rises from to only during S phase, and cell number remains one until cytokinesis, when it becomes two. Which interpretation integrates all three curves?

10. Assertion: The cell plate formed during plant-cell cytokinesis contributes to the region separating the two daughter cells.
Reason: The cell plate acts as a precursor of the new cell wall and represents the future middle lamella between adjacent daughter cells.

11. Two developing systems begin as one cell and gain the same total amount of cellular material. System P becomes one very large uninucleate cell because it never divides. System Q alternates growth with three complete rounds of mitosis and cytokinesis. Which conclusion best explains why Q, but not P, models early multicellular growth?

12. Four cells display the following equatorial arrangements.

Which cell is specifically in metaphase II?

13. A cell has completed S phase and . Microscopy now reveals that diffuse, intertwined chromatin is becoming organised into distinct chromosomes. The cell has most directly entered:

14. Consider the following statements about diplotene.
I. The synaptonemal complex dissolves.
II. Homologous chromosomes begin separating.
III. Homologues remain connected at chiasmata.
IV. Crossing over is initiated for the first time.

15. A circular representation of a cell cycle contains a large sector P followed by a much smaller sector Q. Sector P lies between two successive appearances of sector Q and includes cellular growth and DNA replication. Sector Q most reasonably represents:

16. An oocyte of a vertebrate remains in prophase I for several years. Its homologous chromosomes have begun separating after synaptonemal-complex dissolution but remain connected at chiasmata. This prolonged state is:

17. A treatment allows chromosomes to condense, attach bipolarly and align at the metaphase plate, but it prevents centromere division. If the treatment remains active, the most immediate result will be:

18. Cell P is a haploid plant cell in mitotic metaphase. Cell Q is a metaphase-II cell produced by meiosis I. Both have the condition and align individual replicated chromosomes at the equator. Which evidence specifically identifies Q as meiotic?

19. Recombination is completed normally, but a treatment prevents dissolution of the synaptonemal complex as the cell should enter diplotene. The most direct expected effect is:

20. Use the chromosome movement described here. Replicated homologue P, consisting of sister chromatids P1 and P2, moves towards one pole. Its replicated homologue Q, consisting of Q1 and Q2, moves towards the opposite pole. P1 remains joined to P2, and Q1 remains joined to Q2. The cell is in:

21. Daughter chromosomes reach opposite poles normally, but a treatment prevents their telophase decondensation. Nuclear-envelope components remain available. The most direct consequence is:

22. Eight uninucleate cells each undergo one normal karyokinesis. Cytokinesis succeeds in five cells but fails completely in the remaining three. Immediately afterward, the preparation contains:

23. Four replicated chromosomes show the attachment patterns listed below.

Which chromosome displays the normal mitotic metaphase arrangement?

24. Two daughter nuclei have formed inside one animal cell. A furrow then appears at the cell surface, deepens towards the centre and finally separates the cytoplasm into two compartments. The final process described is:

25. Two cells both have DNA and intact sister-centromere associations. Cell P is preparing for ordinary mitosis, while Cell Q is entering meiosis I. Which observation would identify Cell Q?

26. A population of adult tissue cells shows normal respiration and protein synthesis but no increase in cell number. After neighbouring cells are lost, the population begins DNA replication and division. The original state of these cells was most consistent with:

27. Arrange the following events from established metaphase II to completion of meiosis.
P. Centromeres divide.
Q. Daughter chromosomes move towards opposite poles.
R. Nuclear envelopes form around the chromosome groups.
S. Cytokinesis produces four haploid cells.

28. Arrange the substages of prophase I in their normal order.
P. Pachytene
Q. Leptotene
R. Diakinesis
S. Zygotene
T. Diplotene

29. Control plant cells form a central cell plate that expands until it reaches the lateral walls. Treated cells initiate a central plate, but the plate fails to expand outward and the daughter nuclei remain within one cytoplasmic compartment. The treatment most directly disrupted:

30. Consider the following statements about late prophase.
I. The nucleolus is no longer visibly distinct.
II. The nuclear envelope loses its visible integrity.
III. Golgi complexes and endoplasmic reticulum are not visibly distinct.
IV. Chromosomes begin decondensing into interphase chromatin.

31. Assertion: Meiosis is essential for maintaining a species-specific chromosome number across sexual generations.
Reason: It halves chromosome number before fertilisation, allowing when gametes fuse.

32. A meiocyte is observed at three successive times.

The stage sequence is:

33. A diploid meiocyte has . After premeiotic DNA replication and normal completion of meiosis I, each of the two daughter cells contains:

34. In a meiocyte where nuclear structures reappear after meiosis I, arrange the following events in their broad order.
P. Homologous chromosomes reach opposite poles.
Q. Chromosomes begin dispersing from their condensed state.
R. Nuclear membranes and nucleoli reappear.
S. Cytokinesis produces two cells forming a dyad.

35. Apical meristems and lateral cambium are best classified together as:

36. A cell enters prophase II, but its nuclear membrane fails to disappear. Chromosome compaction occurs normally. The most direct later difficulty would be:

37. An animal cell duplicates its nuclear DNA normally during S phase, but centriole duplication is completely prevented. If the cell is forced into prophase, the most direct structural difficulty will be:

38. Consider the following statements about leptotene.
I. It is the first substage of prophase I.
II. Chromosomes gradually become visible as compaction proceeds.
III. Homologous chromosomes complete synapsis during this stage.
IV. Crossing over between non-sister chromatids occurs during this stage.

39. Consider the following statements about mitosis and organismal growth.
I. Mitosis can increase the number of cells in a developing body.
II. Repeated mitotic divisions allow tissues to arise from a founding cell.
III. Enlargement of one cell alone is sufficient to produce a multicellular organism.
IV. Daughter cells formed by mitosis may grow and divide again.

40. Match each feature with . Meiosis or . Mitosis. Each entry may be reused.
P. Two daughter cells with conserved parental chromosome number
Q. Synapsis of homologous chromosomes
R. Growth and ordinary tissue repair
S. Four haploid products after two divisions

41. Evaluate the following comparisons.
I. Mitosis usually preserves chromosome number in daughter cells.
II. Meiosis I separates homologous chromosomes.
III. Mitosis and meiosis II both involve sister-chromatid separation.
IV. Crossing over is a normal feature of mitotic prophase.

42. Four cell cultures show the following events during one attempted division.

Which culture is most likely to produce two separate daughter cells, each receiving an intact duplicated genome?

43. A treatment permits daughter chromosomes to reach opposite poles and begin decondensing, but it prevents nuclear-envelope formation. The most direct outcome is:

44. Assertion: Meiosis II is a reductional division since DNA content per cell decreases from to .
Reason: Chromosome-set number remains while sister chromatids separate during meiosis II.

45. A graph plots chromosome condensation and nuclear-envelope integrity against progression through a division. Condensation rises as envelope integrity falls, remains high during equatorial alignment and segregation, then falls as envelope integrity rises again. Which interpretation best fits the paired curves?

46. A graph follows one cellular compartment through four successive rounds. Nuclear number rises , while the number of cytoplasmic compartments remains throughout. The graph most directly represents:

47. A fluorescent marker is placed at the centromere of each chromosome, while a second marker labels the chromosome ends. During time-lapse imaging, the centromere markers remain closer to the approaching poles than the end markers. The observation supports the inference that:

48. A species has . Counts refer to one complete cell or one daughter nucleus, as stated.

Which record is biologically inconsistent?

49. A graph plots DNA content per cell on the y-axis against meiotic progression on the x-axis. DNA rises from to before meiosis, falls to after meiosis I, remains constant during interkinesis and falls to after meiosis II. The two decreases differ in that:

50. A treatment triples the duration of but does not alter the rate of cellular growth, chromosome number or the later durations of S, and M phases. Immediately before the delayed cells enter S phase, they are expected to have: