Cell Cycle and Cell Division Mock Test – Class 11 Biology

1. Equal groups of cells undergo three rounds of nuclear division. Group P completes cytokinesis after each round, whereas Group Q completes no cytokinesis. At the end, Group Q contains far fewer cellular compartments but many nuclei within each compartment. The observations support the conclusion that:

2. A graph plots chromosome number per daughter cell and DNA content per daughter cell through meiosis. Chromosome number falls from to after meiosis I and remains after meiosis II. DNA content falls from to and then to . Why does the second DNA decrease lack a further chromosome-number reduction?

3. Assertion: A cell in may contain DNA even though nuclear DNA synthesis is not occurring.
Reason: Nuclear DNA amount normally doubles during .

4. 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.

5. Evaluate these statements about cell-cycle duration.
I. Cultured human cells may complete a cycle in approximately .
II. Yeast may complete a cycle in about .
III. These values illustrate variation in cycle duration among organisms.
IV. Every human cell and every yeast cell must show these exact durations.

6. An unknown cell changes according to the relation , while every chromosome in the product still contains two chromatids. The transition most directly represents:

7. Four cells in prophase I show the following features.

Which cell is in pachytene?

8. If meiotic crossing over were absent in a sexually reproducing population but chromosome segregation and fertilisation remained normal, the most reasonable prediction would be:

9. Consider the following events during anaphase I.
I. Homologous chromosomes move towards opposite poles.
II. Centromeres of sister chromatids remain undivided.
III. Sister chromatids of each chromosome move together.
IV. Each separating chromatid immediately becomes an independent daughter chromosome.

10. Consider the following statements about meiosis in plants and animals.
I. It begins in specialised diploid cells.
II. It contributes to the formation of cells belonging to the haploid phase.
III. It ordinarily preserves the diploid chromosome number in every final product.
IV. It occurs in association with gamete formation.

11. 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:

12. Four cellular intervals are compared below.

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

13. A culture begins with human cells and yeast cells. Assume synchronous division, no cell death and immediate entry of every daughter cell into the next cycle. Human cells require per cycle, while yeast cells require . After , the expected numbers are:

14. The symbolic relation that correctly represents one normal cell through interkinesis is:

15. 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.

16. Assertion: Mitosis in animals cannot be described as occurring exclusively in diploid cells.
Reason: Cells of a haploid male honey bee can undergo mitotic division.

17. Four tissues are observed over the same period.

Which tissue most clearly demonstrates continuous mitotic replacement balancing rapid cell loss?

18. A diploid cell with has entered mitotic anaphase, but cytokinesis has not begun. All centromeres have divided. The complete undivided cell now contains:

19. Four chromosome groups lie at the poles of two dividing haploid cells. Each chromosome consists of one chromatid, and nuclear envelopes are forming around all four groups. The cells are in:

20. A diploid meiocyte produces two cells. Each cell has one chromosome from every homologous pair, but every chromosome still contains two sister chromatids. Nuclear membranes are present, and the chromosomes remain partly condensed. These cells are:

21. A meiocyte completes meiosis I normally, but every metaphase-II chromosome is prevented from dividing its centromere. Cytokinesis associated with meiosis II also fails. The most likely persistent products are:

22. 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:

23. A graph follows a quiescent cell population over time. Cell number remains constant, while oxygen consumption stays well above zero. After a replacement signal is applied, cell number begins to rise. The graph is best interpreted as evidence that:

24. Arrange the following nuclear-envelope changes in their normal meiotic order when telophase-I reconstitution occurs.
P. The envelope disappears during late diakinesis.
Q. It may re-form around chromosome groups in telophase I.
R. It disappears again during prophase II.
S. It forms around the four chromosome groups in telophase II.

25. 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.

26. A replicated chromosome has an intact centromere, but functional kinetochores fail to form on its centromeric surface. The most direct consequence during metaphase would be:

27. Phase distributions are recorded in two large asynchronous cultures.

Which conclusion is most strongly supported without assuming an exact molecular mechanism?

28. 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.

29. Control cells entering late prophase show condensed chromosomes, separated centrosomal regions and loss of visible distinction of the nuclear envelope, nucleolus, Golgi complexes and endoplasmic reticulum. Treated cells show chromosome condensation and centrosomal separation, but all four cellular structures remain visibly distinct. The treatment most directly disrupted:

30. An isolated tissue increases its cell number only when existing cells divide. This observation most directly supports:

31. In a metaphase-I bivalent, both homologous chromosomes become attached to spindle fibres leading towards the same pole, while sister centromeres remain intact. If this arrangement persists, the most direct risk is:

32. A graph follows a diploid cell from through S phase to . Curve P represents DNA amount, and curve Q represents chromosome number counted by centromeres. Which pair of trends is expected?

33. A meiotic cell first shows fully condensed bivalents, terminalised chiasmata and disappearance of the nuclear envelope. Later, the same bivalents form a clear equatorial arrangement with homologues oriented towards opposite poles. The recorded transition is:

34. A replicated chromosome lies at the equator with its sister chromatids joined at one constriction. The constriction divides, and the two resulting structures begin moving towards opposite poles. The cell has entered:

35. Match each structure with its appropriate description during animal-cell mitosis. Each Column II entry is used once.

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

37. 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.

38. A haploid somatic cell of a male honey bee has chromosomes in . After completing S phase, it reaches mitotic metaphase. Which description is correct?

39. Two treatments produce the following results.

Which interpretation best distinguishes the treatments?

40. 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:

41. Control and treated meiocytes complete synapsis normally. In treated cells, recombinase is inactive. No segment exchange is detected during pachytene, and homologues later separate without the usual crossover-associated connections. The treatment most directly explains:

42. A mitotic cell completes DNA replication, but one daughter region receives both copies of a particular chromosome while the other receives none. The most accurate prediction is:

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

44. Under otherwise unchanged conditions, the duration of a proliferating cell’s cycle becomes longer while the observation period remains fixed. The most reasonable prediction is:

45. Two cell cultures increase in mass and complete cytokinesis. In culture P, DNA is replicated and the chromosomes are distributed equally. In culture Q, DNA is replicated but chromosome distribution is irregular. The comparison most strongly demonstrates that:

46. A graph plots DNA content per cell against meiotic progression. The curve falls from to after meiosis I, remains horizontal during interval P and falls to after meiosis II. Interval P represents:

47. Two metabolically active adult-cell populations, P and Q, contain DNA and are not dividing. After a replacement signal, P incorporates a labelled DNA precursor and its cell number later doubles. Q remains unlabelled and its cell number stays constant. The strongest inference is:

48. The observations below were recorded in four dividing cells.

Which pair best contrasts the reductional separation of meiosis I with an equational sister-separation event?

49. A diploid meiocyte has . During zygotene, every chromosome has completed replication and all homologues have formed bivalents. The nucleus contains:

50. Each count below refers to one complete observed cell or final product.

Which sample requires correction?