Cell Cycle and Cell Division Mock Test – Class 11 Biology

1. A treatment blocks centriole duplication during S phase in an animal cell but does not interfere with nuclear DNA replication. Which outcome is most reasonable?

2. Cell P is a haploid plant cell that has completed S phase and will undergo mitosis. Cell Q is an product of meiosis I entering meiosis II. Which comparison is correct?

3. 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.

4. Cells are exposed successively to two treatments. Treatment P prevents nuclear DNA from increasing above . After P is removed, the cells reach , condense chromosomes and align them normally. Treatment Q is then applied; centromeres fail to divide and poleward chromosome separation does not begin. The correct interpretation is:

5. Cells lining a damaged surface are initially lost from one region. Nearby surviving cells enter the cell cycle, duplicate their DNA and divide repeatedly until the exposed area is covered. This response illustrates:

6. A diploid cell has . During prophase after normal S phase, before any centromere has divided, the complete cell contains:

7. Match each prophase change with the corresponding telophase reversal. Each Column II entry is used once.

8. Assertion: Meiosis II is an equational division.
Reason: It separates sister chromatids without causing a further reduction in chromosome-set number.

9. Four cellular intervals are compared below.

Which ordered pair demonstrates the reductional change produced by meiosis I without an intervening round of DNA replication?

10. A replicated chromosome has a structurally intact centromeric region, but no functional kinetochore forms on either sister chromatid. Which outcome is most directly expected?

11. A diploid cell with completes S phase and undergoes normal mitosis. The chromosome-number relation from the parental cell to each daughter cell is:

12. A preparation contains metabolically active adult cells. Exactly are in and do not enter the active cycle during the observation. The remaining cells form an asynchronous cycling population with a cycle, including a S phase. Approximately how many cells should be in S phase at a random observation?

13. A reversibly quiescent cell is stimulated to resume proliferation. Which sequence most accurately represents its return to division?

14. The contrasting directions of cytokinesis in typical animal and plant cells are:

15. During S phase in animal cells, Treatment P permits centriole duplication but prevents nuclear DNA from rising above . Treatment Q permits nuclear DNA to reach but prevents centriole duplication. Which conclusion is most strongly supported?

16. Four diploid cells, each with DNA, show the following features.

Which identification is correct?

17. 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:

18. A plant has a haploid phase with and a diploid phase with . One cell from each phase completes one normal mitosis. The chromosome numbers in the respective daughter cells will be:

19. Two chromosome groups lie at opposite poles, are beginning to decondense and are being enclosed by newly forming nuclear envelopes. The cytoplasm has not yet separated. Which relation between completed and incomplete events is best supported?

20. 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:

21. Evaluate the following statements about interphase.
I. The cell carries out normal metabolic activities.
II. Cellular growth and constituent synthesis may occur.
III. DNA replication occurs during one defined part of interphase.
IV. Interphase consists only of inactivity between two divisions.

22. Control cells form spindle fibres that attach to chromosomes and produce a clear metaphase plate. Treated cells form an apparently bipolar spindle, but their chromosomes remain scattered and show no stable spindle attachment. The treatment most directly affected:

23. Evaluate the following statements about mitotic anaphase.
I. Centromeres divide at its initiation.
II. Sister chromatids become independent daughter chromosomes.
III. Daughter chromosomes move with their arms leading.
IV. Equivalent chromosome groups move towards opposite poles.

24. Three diploid meiocytes, each with , complete normal meiosis independently. Assuming all cytokinetic divisions are completed, the result is:

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

26. Assertion: Named mitotic stages remain useful even though mitosis proceeds through continuous transitions.
Reason: Each stage is recognised by a dominant combination of chromosome organisation, centromere state, spindle relation and nuclear-envelope condition rather than by an instantaneous switch.

27. A dividing diploid cell has completed one DNA-replication phase. Homologous chromosomes pair and exchange segments, two nuclear divisions follow, and four cellular products form. A second diploid cell also completes one replication but shows no homologue pairing and produces two cells after one division. The cells are undergoing:

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

29. 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:

30. Use the chromosome appearance described here. Within a meiotic nucleus, long thread-like chromosomes are becoming progressively more distinct as compaction continues. Homologous chromosomes have not yet begun close pairing. This nucleus is in:

31. Evaluate the following statements.
I. A cell may be in , mitotic metaphase or metaphase I.
II. An cell may be in interkinesis, metaphase II or of a haploid mitotic cycle.
III. A whole anaphase-II cell counted as must have restored diploidy.
IV. The same - state can occur in different biological histories.

32. Arrange the following events in their normal order.
P. Synapsis establishes a bivalent.
Q. Four chromatids become distinct and recombination nodules appear.
R. Recombination is completed by the end of pachytene.
S. The synaptonemal complex dissolves and chiasmata become evident.

33. Evaluate these statements about normal mitosis.
I. Each daughter cell ordinarily receives the same chromosome number as the parental cell.
II. DNA replication before mitosis temporarily doubles the chromosome number.
III. A haploid parent cell can produce haploid daughter cells by mitosis.
IV. Equational division refers to conservation of chromosome number in the products.

34. An asynchronous culture has a cell cycle consisting of of , of S phase, of and of M phase. Among randomly sampled cells, the expected numbers in S phase and M phase are approximately:

35. A species has . In Cell P, five X-shaped replicated chromosomes move towards each pole while sister centromeres remain intact. In each of two Cells Q, five V-shaped single-chromatid chromosomes move towards each pole with centromeres leading. Which identification is correct?

36. Arrange the following events in their normal cell-cycle order in an animal cell.
P. Many cellular constituents and organelles increase while nuclear DNA remains .
Q. Nuclear DNA reaches , and centrioles have duplicated in the cytoplasm.
R. Growth continues and proteins required for mitosis are synthesised.
S. Duplicated centrosomal regions move apart and the mitotic apparatus develops.

37. Two equally grown cells complete normal karyokinesis. Cell P partitions its cytoplasm nearly equally, whereas Cell Q forms one large and one very small cytoplasmic compartment despite producing equivalent daughter nuclei. Which inference about nucleo-cytoplasmic balance is most justified?

38. During plant-cell cytokinesis, the distance from the centre of the cell to the advancing edge of a partition is plotted against time. The distance rises steadily until the partition meets the lateral walls. Which conclusion best integrates the graph with the later fate of the partition?

39. DNA changes during meiosis are summarised below for one diploid meiocyte and its products.

Which interpretation is supported by the complete record?

40. Two meiocytes show the following features.

The transition from Cell P to Cell Q most directly represents:

41. Assertion: Assuming no DNA loss, the four final products of one meiosis together contain the same total DNA as the original meiocyte immediately after premeiotic S phase.
Reason: The decreases from to and then are per-cell changes caused by partitioning DNA among two and then four products.

42. 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.

43. Arrange the following changes in their broad progression from the end of interphase to established metaphase.
P. Chromatin starts condensing into visible chromosomes.
Q. Duplicated centrosomes move towards opposite poles.
R. Nuclear-envelope distinction is lost.
S. Chromosomes become available for spindle-dependent equatorial alignment.

44. The observations below were recorded for normal mitotic divisions.

Which conclusion is best supported by the complete data?

45. Which combination correctly evaluates these statements?
I. A rise in cell mass alone is insufficient to identify S phase.
II. An increase in nuclear DNA amount is evidence that the cell is in S phase.
III. Cellular growth may continue outside the period of DNA synthesis.
IV. Nuclear DNA doubles gradually throughout all of interphase.

46. A growing cell initially has a nuclear volume of and a cytoplasmic volume of . Before division, its cytoplasm increases to , while nuclear volume remains . After normal mitosis and equal cytokinesis, each daughter is measured with a nucleus and of cytoplasm. The cytoplasmic-volume-to-nuclear-volume ratios are:

47. A diploid cell contains chromosomes in . After completing S phase, but before centromere division, the same cell contains:

48. A graph follows one diploid cell through , metaphase, undivided anaphase and completed cytokinesis. Curve P records DNA content per observed cellular unit, while Curve Q records chromosome number by centromeres. Each option gives the values at , metaphase, undivided anaphase and after cytokinesis, respectively. Which trend is expected?

49. Three adult-cell populations are described.
Population P remains metabolically active but does not ordinarily divide, as in adult heart tissue.
Population Q is non-proliferative under normal conditions but re-enters the cycle after cell loss.
Population R continually passes through the cycle to replace rapidly lost cells.
The most appropriate classification is:

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