TRB PG Assistant - Cell division – mitosis, meiosis, regulation and significance Online Test (MCQ Quiz)

1. What is the primary purpose of mitosis?

A) To produce gametes for sexual reproduction B) To increase genetic variation in offspring C) To produce genetically identical daughter cells for growth and repair D) To reduce the chromosome number by half

2. Which phase of mitosis is characterized by the alignment of chromosomes at the metaphase plate?

A) Prophase B) Prometaphase C) Metaphase D) Anaphase

3. During which phase of the cell cycle does DNA replication occur?

A) G1 phase B) S phase C) G2 phase D) M phase

4. Meiosis is a type of cell division that results in:

A) Four diploid cells B) Two haploid cells C) Four haploid cells D) Two diploid cells

5. What is the term for the specialized structure formed by microtubules during mitosis and meiosis that separates chromosomes?

A) Centrosome B) Spindle apparatus C) Kinetochore D) Cell plate

6. Crossing over, an important event in meiosis that contributes to genetic diversity, occurs during which phase?

A) Leptotene B) Zygotene C) Pachytene D) Diplotene

7. Which protein complex acts as a 'molecular clock' and regulates the progression through the cell cycle checkpoints?

A) Cyclin-dependent kinases (CDKs) B) Actin C) Myosin D) Tubulin

8. In mitosis, sister chromatids separate and move to opposite poles during:

A) Metaphase B) Anaphase C) Telophase D) Cytokinesis

9. What is the significance of cytokinesis?

A) Replication of genetic material B) Separation of homologous chromosomes C) Division of the cytoplasm to form two daughter cells D) Formation of the nuclear envelope

10. Which of the following is a key difference between mitosis and meiosis I?

A) Mitosis involves homologous chromosome pairing, while meiosis I does not. B) Meiosis I separates sister chromatids, while mitosis separates homologous chromosomes. C) Meiosis I separates homologous chromosomes, while mitosis separates sister chromatids. D) Mitosis produces haploid cells, while meiosis I produces diploid cells.

11. What are cyclins?

A) Enzymes that phosphorylate other proteins B) Proteins whose concentrations fluctuate cyclically during the cell cycle C) Structures that hold sister chromatids together D) Components of the cell wall in plant cells

12. The G1 checkpoint, also known as the restriction point, primarily assesses:

A) Completion of DNA replication B) Proper spindle formation C) Cell size, nutrients, and growth factors D) Chromosome segregation

13. What is the term for the point where homologous chromosomes are connected during diplotene of meiosis I?

A) Centromere B) Kinetochore C) Chiasma D) Synaptonemal complex

14. Which type of cell division occurs in somatic cells?

A) Mitosis B) Meiosis C) Both mitosis and meiosis D) Neither mitosis nor meiosis

15. The formation of the synaptonemal complex is characteristic of which stage of meiosis?

A) Zygotene B) Pachytene C) Diplotene D) Diakinesis

16. What is the role of p53 in cell cycle regulation?

A) It promotes entry into the S phase. B) It activates CDKs to drive cell division. C) It can halt the cell cycle if DNA damage is detected, allowing for repair. D) It is responsible for the separation of sister chromatids.

17. During anaphase II of meiosis, what is separated?

A) Homologous chromosomes B) Sister chromatids C) Centromeres D) Telomeres

18. Which organism was famously used by E.B. Wilson to study chromosome behavior during cell division?

A) Drosophila melanogaster (fruit fly) B) Caenorhabditis elegans (nematode) C) Ascaris megalocephala (roundworm) D) Saccharomyces cerevisiae (yeast)

19. The G2 checkpoint ensures that:

A) The cell has grown sufficiently B) DNA replication is complete and any errors are repaired C) Chromosomes are correctly attached to the spindle D) The cell is ready to exit the cell cycle

20. What is the primary significance of meiosis in sexual reproduction?

A) To produce identical offspring B) To maintain a constant chromosome number across generations C) To increase the size of somatic cells D) To generate genetically diverse gametes

21. Which of the following is a key event of telophase in mitosis?

A) Chromosomes condense B) Nuclear envelopes reform around separated chromosomes C) Sister chromatids separate D) Homologous chromosomes pair up

22. The spindle assembly checkpoint (SAC) monitors:

A) The integrity of the cell membrane B) The attachment of all chromosomes to the spindle microtubules C) The rate of DNA synthesis D) The overall metabolic activity of the cell

23. What is a consequence of uncontrolled cell division?

A) Apoptosis B) Senescence C) Cancer D) Meiotic arrest

24. In plant cells, cytokinesis involves the formation of:

A) A cleavage furrow B) A cell plate C) A spindle apparatus D) A nuclear envelope

25. During which phase of meiosis do homologous chromosomes separate?

A) Prophase I B) Metaphase I C) Anaphase I D) Anaphase II

26. What are centrosomes and their role in mitosis?

A) Organelles that produce ATP; they are involved in energy production. B) Microtubule-organizing centers; they form the spindle fibers. C) Sites of protein synthesis; they are involved in ribosome production. D) Storage granules; they hold reserve food materials.

27. The term 'ploidy' refers to:

A) The number of chromosomes in a cell B) The number of sets of chromosomes in a cell C) The size of the nucleus D) The stage of the cell cycle

28. Which of the following is NOT a stage of mitosis?

A) Prophase B) Metaphase C) Interphase D) Telophase

29. What happens to the nuclear envelope during prophase of mitosis?

A) It reforms around the chromosomes. B) It breaks down into small vesicles. C) It remains intact throughout the phase. D) It divides into two separate envelopes.

30. The formation of bivalents (or tetrads) is a hallmark of which stage?

A) Mitotic prophase B) Meiotic prophase I C) Mitotic metaphase D) Meiotic metaphase II

31. Which protein is primarily responsible for degrading cyclins to allow progression through the cell cycle?

A) Cyclin-dependent kinase (CDK) B) Anaphase-promoting complex/cyclosome (APC/C) C) Retinoblastoma protein (Rb) D) p53

32. What is the end product of meiosis in males?

A) One sperm cell and three polar bodies B) Four sperm cells C) Two sperm cells D) One ovum and three polar bodies

33. During anaphase of mitosis, the centromeres divide, and sister chromatids become:

A) Homologous chromosomes B) Daughter chromosomes C) Bivalents D) Tetrads

34. The G0 phase of the cell cycle is characterized by:

A) Rapid cell division B) DNA replication C) A quiescent state outside the cell cycle D) Chromosome condensation

35. What is the significance of the synaptonemal complex?

A) It facilitates the separation of sister chromatids. B) It holds homologous chromosomes together during synapsis. C) It is involved in the formation of the mitotic spindle. D) It regulates the G1 checkpoint.

36. Which statement best describes the outcome of meiosis II?

A) Separation of homologous chromosomes B) Reduction of chromosome number by half C) Separation of sister chromatids in haploid cells D) Production of genetically identical daughter cells

37. Apoptosis, or programmed cell death, is a crucial process for:

A) Tissue regeneration and development B) Increasing cell population C) DNA replication D) Maintaining genetic stability

38. What is the role of kinetochores in cell division?

A) They are responsible for DNA replication. B) They are protein structures on centromeres where spindle fibers attach. C) They initiate the breakdown of the nuclear envelope. D) They signal the cell to exit the cell cycle.

39. If a diploid organism has 2n = 16 chromosomes, how many chromosomes will be present in each daughter cell after mitosis?

A) 8 B) 16 C) 32 D) 4

40. Which phase of mitosis is characterized by the decondensation of chromosomes and the reformation of the nuclear envelope?

A) Prophase B) Metaphase C) Anaphase D) Telophase

41. The term 'gamete' refers to:

A) A somatic cell B) A cell involved in growth and repair C) A reproductive cell (sperm or egg) D) A cell undergoing mitosis

42. Which of the following is a key difference between cytokinesis in animal and plant cells?

A) Animal cells form a cell plate, while plant cells form a cleavage furrow. B) Plant cells form a cell plate, while animal cells form a cleavage furrow. C) Animal cells divide by budding, while plant cells divide by fission. D) Plant cells do not undergo cytokinesis.

43. What is the significance of the M checkpoint (spindle checkpoint)?

A) It ensures the cell is large enough to divide. B) It checks for DNA damage before replication. C) It ensures that all chromosomes are properly attached to the spindle before anaphase begins. D) It regulates the transition from G2 to M phase.

44. During diakinesis of meiosis I, the chromosomes:

A) Replicate their DNA. B) Align at the metaphase plate. C) Reach maximum condensation and chiasmata become visible. D) Separate into sister chromatids.

45. Which of the following is a product of mitosis?

A) Two genetically identical diploid cells B) Four genetically diverse haploid cells C) Two genetically different diploid cells D) Four genetically identical haploid cells

46. The term 'diploid' refers to a cell having:

A) One set of chromosomes B) Two sets of chromosomes C) More than two sets of chromosomes D) No chromosomes

47. Which phase of meiosis is most similar to mitosis in terms of chromosome behavior?

A) Meiosis I B) Meiosis II C) Interphase D) None of the above

48. What is the primary function of cyclins in cell cycle regulation?

A) To bind to and activate CDKs B) To phosphorylate target proteins C) To degrade CDK proteins D) To halt the cell cycle at checkpoints

49. The failure of homologous chromosomes to separate during meiosis I is called:

A) Nondisjunction B) Translocation C) Inversion D) Deletion

50. Which of the following is a key regulatory protein that, when mutated, can lead to uncontrolled cell proliferation and cancer?

A) Actin B) Tubulin C) p53 D) Histone

Cell division – mitosis, meiosis, regulation and significance - Online Test

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