Cell division MCQs With Answer designed for B.Pharm students provide a focused, exam-ready review of mitosis, meiosis, cytokinesis, and cell cycle regulation. This concise, high-yield introduction covers key concepts such as phases of the cell cycle, cyclins and CDKs, checkpoints, chromosome behavior, and mechanisms of DNA replication and repair. Emphasis on pharmacological implications—anticancer drugs, mitotic inhibitors, and molecular targets—helps bridge theory and therapeutics. Each question includes detailed options and is tailored to strengthen conceptual clarity and application. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. Which phase of the cell cycle is primarily responsible for DNA synthesis?
- G1 phase
- S phase
- G2 phase
- M phase
Correct Answer: S phase
Q2. Which protein complex directly phosphorylates target proteins to drive cell cycle progression?
- Cyclin-dependent kinase (CDK) bound to cyclin
- DNA polymerase holoenzyme
- Topoisomerase II complex
- Apoptosome
Correct Answer: Cyclin-dependent kinase (CDK) bound to cyclin
Q3. During which mitotic stage do sister chromatids separate and move to opposite poles?
- Prophase
- Metaphase
- Anaphase
- Telophase
Correct Answer: Anaphase
Q4. Which checkpoint ensures DNA is fully replicated and undamaged before mitosis?
- G1/S checkpoint
- Spindle assembly checkpoint
- G2/M checkpoint
- Restriction point
Correct Answer: G2/M checkpoint
Q5. Which of the following cyclins peaks during S phase?
- Cyclin D
- Cyclin E
- Cyclin A
- Cyclin B
Correct Answer: Cyclin A
Q6. Meiosis differs from mitosis primarily because meiosis results in:
- Two genetically identical diploid cells
- Four genetically distinct haploid cells
- One tetraploid cell
- Two haploid cells identical to parent
Correct Answer: Four genetically distinct haploid cells
Q7. Which event creates genetic recombination during meiosis I?
- Independent assortment only
- Sister chromatid separation
- Crossing over (chiasmata formation)
- Cytokinesis
Correct Answer: Crossing over (chiasmata formation)
Q8. The kinetochore attaches to which structure during chromosome segregation?
- Centromere DNA directly
- Microtubules of the mitotic spindle
- Actin filaments of contractile ring
- Intermediate filaments
Correct Answer: Microtubules of the mitotic spindle
Q9. Which protein is known as the “guardian of the genome” and mediates DNA damage response?
- Rb (Retinoblastoma protein)
- p53
- BRCA1
- MDM2
Correct Answer: p53
Q10. Cytokinesis in plant cells is characterized by formation of:
- Contractile ring of actin and myosin
- Cell plate from vesicles
- Cleavage furrow only
- New centrosome between daughter cells
Correct Answer: Cell plate from vesicles
Q11. Which enzyme relieves supercoiling ahead of the replication fork?
- DNA ligase
- Helicase
- Topoisomerase
- Primase
Correct Answer: Topoisomerase
Q12. Which of the following drugs targets microtubules and is used as an antimitotic agent?
- 5-Fluorouracil
- Vincristine
- Oxaliplatin
- Bleomycin
Correct Answer: Vincristine
Q13. Cohesin complexes are primarily responsible for:
- Condensing chromosomes during prophase
- Holding sister chromatids together
- Initiating DNA replication
- Forming the mitotic spindle
Correct Answer: Holding sister chromatids together
Q14. Nondisjunction during meiosis can result in:
- Balanced translocation
- Aneuploid gametes
- Point mutation accumulation
- Chromosome inversion
Correct Answer: Aneuploid gametes
Q15. Which marker is commonly used to assess proliferative index in tumor samples?
- Caspase-3 expression
- Ki-67 antigen
- p21 expression
- Annexin V binding
Correct Answer: Ki-67 antigen
Q16. Licensing of replication origins in eukaryotes occurs in which phase?
- G1 phase
- S phase
- G2 phase
- M phase
Correct Answer: G1 phase
Q17. Which structure forms the spindle poles in animal cells?
- Centrosomes with centrioles
- Cell plate
- Contractile ring
- Golgi apparatus
Correct Answer: Centrosomes with centrioles
Q18. What is the primary role of condensin complexes during mitosis?
- DNA repair after replication
- Chromosome condensation and stabilization
- Degradation of cyclins
- Attachment of kinetochores to microtubules
Correct Answer: Chromosome condensation and stabilization
Q19. The spindle assembly checkpoint prevents anaphase onset until:
- DNA replication is complete
- All kinetochores are properly attached to microtubules
- Cell has sufficient nutrients
- Cytokinesis begins
Correct Answer: All kinetochores are properly attached to microtubules
Q20. Which of the following best describes S-phase inhibitors used in chemotherapy?
- They prevent spindle formation
- They block DNA synthesis
- They induce membrane lysis
- They inhibit protein translation
Correct Answer: They block DNA synthesis
Q21. In bacterial binary fission, which protein is essential for septum formation?
- FtsZ
- RecA
- DNA gyrase
- Rho factor
Correct Answer: FtsZ
Q22. Which histone modification is most directly associated with transcriptionally active chromatin during S phase?
- Histone H3K9 methylation
- Histone H3K27 methylation
- Histone acetylation (e.g., H3K9ac)
- Histone ubiquitination leading to silencing
Correct Answer: Histone acetylation (e.g., H3K9ac)
Q23. Which enzyme seals Okazaki fragments on the lagging strand?
- DNA polymerase I
- DNA ligase
- Primase
- RNase H
Correct Answer: DNA ligase
Q24. Which phase of meiosis involves separation of homologous chromosomes?
- Anaphase II
- Anaphase I
- Telophase II
- Metaphase II
Correct Answer: Anaphase I
Q25. Which tumor suppressor protein inhibits G1 to S transition by controlling E2F transcription factors?
- p53
- Rb (Retinoblastoma protein)
- Myc
- MDM2
Correct Answer: Rb (Retinoblastoma protein)
Q26. Which technique measures DNA content and can estimate cell cycle distribution?
- Western blotting
- Flow cytometry with DNA staining
- ELISA for cyclins
- Immunohistochemistry for Ki-67 only
Correct Answer: Flow cytometry with DNA staining
Q27. Telomerase activity is typically highest in which cell type?
- Most somatic cells
- Stem cells and germ cells
- Terminally differentiated neurons
- Senescent fibroblasts
Correct Answer: Stem cells and germ cells
Q28. Which of the following is a hallmark of apoptosis rather than necrosis?
- Cell swelling and membrane rupture
- Inflammatory response
- Chromatin condensation and DNA laddering
- Immediate loss of plasma membrane integrity
Correct Answer: Chromatin condensation and DNA laddering
Q29. Which protein targets cyclins for degradation at the end of mitosis?
- APC/C (Anaphase-Promoting Complex/Cyclosome)
- SCF complex
- Proteasome alone without ubiquitination
- Topoisomerase I
Correct Answer: APC/C (Anaphase-Promoting Complex/Cyclosome)
Q30. Which phase is often shortened in rapidly dividing cancer cells, contributing to high proliferation?
- G0 phase extension
- G1 phase shortening
- S phase extension
- M phase elongation
Correct Answer: G1 phase shortening
Q31. Which structure distinguishes metaphase from prometaphase during mitosis?
- Chromosomes condensing
- Formation of nuclear envelope
- Chromosomes aligned at the metaphase plate
- Initiation of DNA replication
Correct Answer: Chromosomes aligned at the metaphase plate
Q32. BRCA1 mutation primarily affects which cellular process relevant to cell division?
- Mismatch repair only
- Homologous recombination DNA repair
- RNA splicing fidelity
- Centrosome duplication exclusively
Correct Answer: Homologous recombination DNA repair
Q33. Which of the following events occurs during prophase of mitosis?
- Nuclear envelope reformation
- Chromosomes condense and become visible
- Sister chromatids separate
- Chromosomes align at equator
Correct Answer: Chromosomes condense and become visible
Q34. A cell arrested at the restriction point (R) is prevented from entering:
- M phase directly
- S phase and DNA synthesis
- Cytokinesis only
- G2 checkpoint
Correct Answer: S phase and DNA synthesis
Q35. Which of the following best explains centrosome amplification in cancer?
- Frequent DNA replication errors only
- Overduplication of centrosomes leading to multipolar spindles
- Enhanced cytokinesis efficiency
- Increased telomerase activity exclusively
Correct Answer: Overduplication of centrosomes leading to multipolar spindles
Q36. Which enzyme synthesizes RNA primers required for DNA replication?
- DNA polymerase III
- Primase
- DNA ligase
- Helicase
Correct Answer: Primase
Q37. Which event is unique to meiosis II compared to meiosis I?
- Synapsis of homologous chromosomes
- Separation of sister chromatids
- Reductional division (reduction in chromosome number)
- Crossing over
Correct Answer: Separation of sister chromatids
Q38. Which chemical agent disrupts mitosis by depolymerizing microtubules?
- Paclitaxel (Taxol)
- Colchicine
- Cisplatin
- Hydroxyurea
Correct Answer: Colchicine
Q39. Which checkpoint protein inhibits CDK activity in response to DNA damage?
- Cyclin B
- p21 (CDK inhibitor)
- Rb protein activating E2F
- Cdc25 phosphatase
Correct Answer: p21 (CDK inhibitor)
Q40. Which assay is used to detect DNA fragmentation during apoptosis?
- Comet assay or TUNEL assay
- MTT assay for cell viability
- Flow cytometry for cell cycle only
- Western blot for tubulin
Correct Answer: Comet assay or TUNEL assay
Q41. What does a high mitotic index indicate in a tumor biopsy?
- Low proliferative activity
- High proportion of cells undergoing mitosis
- High apoptotic rate only
- Complete cell cycle arrest
Correct Answer: High proportion of cells undergoing mitosis
Q42. Which DNA replication problem is addressed by telomerase?
- Mismatch base pairing
- End replication problem at chromosome termini
- Removal of RNA primers
- Fixing double-strand breaks
Correct Answer: End replication problem at chromosome termini
Q43. Which of the following proteins activates the anaphase-promoting complex to trigger sister chromatid separation?
- Cdc20
- Securin only
- Cohesin
- SMC proteins
Correct Answer: Cdc20
Q44. During metaphase I of meiosis, homologous chromosomes align:
- Individually at the metaphase plate
- As homologous pairs (tetrads) at the metaphase plate
- Along the cell periphery only
- They do not align in metaphase I
Correct Answer: As homologous pairs (tetrads) at the metaphase plate
Q45. Which protein family promotes progression through G1 by phosphorylating Rb?
- CDK inhibitors (CKIs) like p21
- Cyclin D-CDK4/6 complexes
- APC/C activators
- DNA helicases
Correct Answer: Cyclin D-CDK4/6 complexes
Q46. Which laboratory technique is commonly used to visualize karyotypes and detect large chromosomal abnormalities?
- Southern blotting
- G-banded karyotyping
- PCR amplification of genes
- Northern blotting
Correct Answer: G-banded karyotyping
Q47. Which process restores DNA continuity after removal of RNA primers?
- DNA ligase seals nicks after DNA polymerase replaces primers
- Helicase synthesizes new DNA
- Cohesin removes primers
- Topoisomerase fills gaps
Correct Answer: DNA ligase seals nicks after DNA polymerase replaces primers
Q48. Which event signals the completion of mitosis and initiation of cytokinesis?
- Entry into S phase
- Activation of APC/C and degradation of securin
- Duplication of centrosomes
- DNA replication licensing
Correct Answer: Activation of APC/C and degradation of securin
Q49. In oogenesis, meiosis is arrested at prophase I until which event resumes meiosis?
- Fertilization or hormonal signals at puberty depending on species
- Completion of S phase
- Telophase II spontaneously
- Entry into G0 permanently
Correct Answer: Fertilization or hormonal signals at puberty depending on species
Q50. Which molecular change often leads to immortalization of cells and is relevant to cancer biology?
- Loss of telomerase activity
- Activation of telomerase allowing indefinite replication
- Permanent cell cycle arrest in G0
- Enhanced DNA repair leading to senescence
Correct Answer: Activation of telomerase allowing indefinite replication
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