MCQs on Cell Cycle and Cell Division – Class 11 Biology
MCQs on Cell Cycle and Cell Division – CBSE Class 11 Biology (Unit III | NCERT-Based)
CBSE Class 11 Biology – MCQs with Answers and Explanations
Unit III: Cell Structure and Function
Topic: Cell Cycle and Cell Division
Section A: Cell Cycle & Its Phases (Q1–Q10)
Q1. The sequence of events by which a cell duplicates its contents and divides is called:
A. Cell differentiation
B. Cell cycle
C. Cell division
D. Cytokinesis
Answer: B
Explanation: The cell cycle includes all stages from one cell division to the next, including growth, DNA replication, and division.
Q2. The longest phase of the cell cycle is:
A. Mitosis
B. G₁ phase
C. S phase
D. Interphase
Answer: D
Explanation: Interphase occupies most of the cell cycle and includes G₁, S, and G₂ phases.
Q3. DNA replication occurs during:
A. G₁ phase
B. S phase
C. G₂ phase
D. M phase
Answer: B
Explanation: In the S (synthesis) phase, DNA content of the cell doubles.
Q4. The G₁ phase is mainly involved in:
A. DNA replication
B. Cell division
C. Cell growth and metabolism
D. Chromosome alignment
Answer: C
Explanation: G₁ phase is a period of active growth and synthesis of proteins and RNA.
Q5. Cells that do not divide further enter the:
A. G₁ phase
B. S phase
C. G₂ phase
D. G₀ phase
Answer: D
Explanation: G₀ phase is a resting or quiescent stage where cells exit the cell cycle.
Q6. The phase immediately preceding mitosis is:
A. G₁
B. S
C. G₂
D. Cytokinesis
Answer: C
Explanation: G₂ phase prepares the cell for mitosis by synthesizing necessary proteins.
Q7. Which phase shows maximum metabolic activity?
A. G₁ phase
B. S phase
C. G₂ phase
D. M phase
Answer: A
Explanation: G₁ phase involves intense biosynthetic activities.
Q8. Interphase is incorrectly referred to as a resting phase because:
A. No activity occurs
B. Cell prepares for division
C. DNA is inactive
D. Cell shrinks
Answer: B
Explanation: Interphase is metabolically active and prepares the cell for division.
Q9. The total number of phases in interphase is:
A. One
B. Two
C. Three
D. Four
Answer: C
Explanation: Interphase consists of G₁, S, and G₂ phases.
Q10. Which phase marks the beginning of DNA synthesis?
A. G₀
B. G₁
C. S
D. G₂
Answer: C
Explanation: DNA replication starts in the S phase.
Section B: Mitosis – Stages and Significance (Q11–Q30)
Q11. Mitosis occurs mainly in:
A. Germ cells
B. Somatic cells
C. Meiocytes
D. Gametes
Answer: B
Explanation: Mitosis is responsible for growth and repair in somatic cells.
Q12. The first stage of mitosis is:
A. Metaphase
B. Anaphase
C. Prophase
D. Telophase
Answer: C
Explanation: Prophase initiates mitosis with chromosome condensation.
Q13. Chromosomes become clearly visible during:
A. Interphase
B. Prophase
C. Anaphase
D. Telophase
Answer: B
Explanation: Chromatin condenses into visible chromosomes in prophase.
Q14. Disappearance of nuclear membrane occurs in:
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Answer: A
Explanation: Nuclear envelope breaks down during prophase.
Q15. Chromosomes align at the equatorial plate during:
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Answer: B
Explanation: In metaphase, chromosomes line up at the cell equator.
Q16. The centromere splits during:
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Answer: C
Explanation: Centromere division allows sister chromatids to separate in anaphase.
Q17. Movement of chromatids towards opposite poles occurs in:
A. Metaphase
B. Anaphase
C. Telophase
D. Prophase
Answer: B
Explanation: Anaphase is characterized by chromatid separation.
Q18. Reformation of nuclear membrane occurs during:
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Answer: D
Explanation: Telophase restores the nuclear envelope and nucleolus.
Q19. Cytokinesis in animal cells occurs by:
A. Cell plate formation
B. Fragmentation
C. Cleavage furrow
D. Budding
Answer: C
Explanation: Animal cells divide cytoplasm by forming a cleavage furrow.
Q20. Cytokinesis in plant cells occurs by:
A. Cleavage furrow
B. Cell plate formation
C. Budding
D. Constriction
Answer: B
Explanation: Plant cells form a cell plate due to rigid cell walls.
Q21. The spindle fibres are composed of:
A. Actin filaments
B. Microtubules
C. Microfilaments
D. Intermediate filaments
Answer: B
Explanation: Spindle fibres are made of microtubules.
Q22. Which stage is the shortest in mitosis?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Answer: C
Explanation: Anaphase is short as chromatids separate rapidly.
Q23. Which of the following is a significance of mitosis?
A. Genetic variation
B. Reduction in chromosome number
C. Growth and repair
D. Gamete formation
Answer: C
Explanation: Mitosis enables growth, tissue repair, and regeneration.
Q24. The chromosome number after mitosis remains:
A. Reduced
B. Doubled
C. Same as parent cell
D. Zero
Answer: C
Explanation: Mitosis maintains genetic stability.
Q25. Which phase is called the equational division?
A. Meiosis I
B. Meiosis II
C. Mitosis
D. Prophase I
Answer: C
Explanation: Mitosis produces daughter cells with equal chromosome number.
Q26. Which structure connects spindle fibres to chromosomes?
A. Centriole
B. Kinetochore
C. Centrosome
D. Chromatid
Answer: B
Explanation: Kinetochore is the attachment point for spindle fibres.
Q27. Which organelle organizes spindle formation in animal cells?
A. Lysosome
B. Golgi apparatus
C. Centriole
D. Ribosome
Answer: C
Explanation: Centrioles organize spindle fibres.
Q28. Mitosis without cytokinesis results in:
A. Anucleate cells
B. Multinucleate cells
C. Haploid cells
D. Polyploid cells
Answer: B
Explanation: Nuclear division without cytoplasmic division forms multinucleate cells.
Q29. Amitosis is characterized by:
A. Spindle formation
B. Chromosome condensation
C. Direct nuclear division
D. Cytokinesis only
Answer: C
Explanation: Amitosis involves direct division without spindle apparatus.
Q30. Mitosis is essential for:
A. Gamete formation
B. Genetic variation
C. Embryonic development
D. Reduction division
Answer: C
Explanation: Embryonic growth requires repeated mitotic divisions.
Section C: Meiosis – Stages and Importance (Q31–Q50)
Q31. Meiosis occurs in:
A. Somatic cells
B. Germ cells
C. Nerve cells
D. Muscle cells
Answer: B
Explanation: Meiosis occurs in germ cells to form gametes.
Q32. Meiosis involves how many divisions?
A. One
B. Two
C. Three
D. Four
Answer: B
Explanation: Meiosis includes Meiosis I and Meiosis II.
Q33. Reduction of chromosome number occurs in:
A. Mitosis
B. Meiosis I
C. Meiosis II
D. Cytokinesis
Answer: B
Explanation: Meiosis I is the reductional division.
Q34. Pairing of homologous chromosomes is called:
A. Crossing over
B. Synapsis
C. Terminalization
D. Chiasma
Answer: B
Explanation: Synapsis occurs during prophase I.
Q35. Crossing over occurs during:
A. Leptotene
B. Zygotene
C. Pachytene
D. Diplotene
Answer: C
Explanation: Exchange of genetic material occurs in pachytene stage.
Q36. Chiasmata are visible during:
A. Pachytene
B. Diplotene
C. Diakinesis
D. Metaphase I
Answer: B
Explanation: Chiasmata become visible in diplotene.
Q37. Separation of homologous chromosomes occurs in:
A. Anaphase I
B. Anaphase II
C. Metaphase I
D. Telophase II
Answer: A
Explanation: Homologous chromosomes separate during anaphase I.
Q38. Meiosis II is similar to:
A. Meiosis I
B. Mitosis
C. Amitosis
D. Cytokinesis
Answer: B
Explanation: Meiosis II resembles mitosis (equational division).
Q39. The chromosome number in daughter cells after meiosis is:
A. Diploid
B. Triploid
C. Haploid
D. Tetraploid
Answer: C
Explanation: Meiosis produces haploid gametes.
Q40. Genetic variation arises during meiosis due to:
A. Cytokinesis
B. DNA replication
C. Crossing over
D. Cell growth
Answer: C
Explanation: Crossing over leads to recombination of genes.
Q41. Independent assortment occurs during:
A. Prophase I
B. Metaphase I
C. Anaphase I
D. Telophase I
Answer: B
Explanation: Random orientation of homologous pairs occurs in metaphase I.
Q42. The stage showing maximum chromosomal condensation is:
A. Leptotene
B. Zygotene
C. Pachytene
D. Diakinesis
Answer: D
Explanation: Chromosomes are shortest and thickest in diakinesis.
Q43. How many daughter cells are formed after meiosis?
A. Two
B. Three
C. Four
D. Eight
Answer: C
Explanation: Meiosis produces four haploid daughter cells.
Q44. Which process ensures constancy of chromosome number across generations?
A. Mitosis
B. Meiosis
C. Fertilization
D. Cytokinesis
Answer: B
Explanation: Meiosis halves the chromosome number in gametes.
Q45. Which division is termed reduction division?
A. Mitosis
B. Meiosis I
C. Meiosis II
D. Amitosis
Answer: B
Explanation: Meiosis I reduces chromosome number to half.
Q46. Terminalization of chiasmata occurs during:
A. Diplotene
B. Pachytene
C. Diakinesis
D. Metaphase I
Answer: C
Explanation: Chiasmata move towards chromosome ends in diakinesis.
Q47. Which phase involves pairing of homologous chromosomes?
A. Prophase
B. Prophase I
C. Metaphase
D. Anaphase
Answer: B
Explanation: Pairing occurs in prophase I of meiosis.
Q48. Failure of chromosome separation is called:
A. Mutation
B. Synapsis
C. Nondisjunction
D. Translocation
Answer: C
Explanation: Nondisjunction leads to abnormal chromosome number.
Q49. Meiosis is essential for sexual reproduction because it:
A. Causes growth
B. Repairs tissues
C. Produces gametes
D. Prevents mutation
Answer: C
Explanation: Gamete formation requires meiosis.
Q50. Which division introduces genetic variability?
A. Mitosis
B. Amitosis
C. Meiosis
D. Cytokinesis
Answer: C
Explanation: Meiosis introduces variation through crossing over and independent assortment.