ICSE Class 10 Biology: Cell Division — Important Questions with Answers 2026

Short Answer Questions (2-3 Marks)

• Q: Differentiate between mitosis and meiosis (any 5 points).
  Ans: Mitosis: occurs in somatic cells, 2 identical daughter cells, chromosome number maintained (2n→2n), no crossing over, single division. Meiosis: occurs in reproductive cells, 4 daughter cells with half chromosomes, chromosome number halved (2n→n), crossing over occurs in prophase I, two divisions (meiosis I and II). Significance: Mitosis for growth and repair, Meiosis for gamete formation and genetic variation.
• Q: Describe the stages of mitosis.
  Ans: Prophase: Chromatin condenses into chromosomes, each with 2 chromatids. Nuclear membrane and nucleolus disappear. Centrioles move to poles. Metaphase: Chromosomes align at cell equator (metaphase plate). Spindle fibres attach to centromeres. Anaphase: Centromeres split, chromatids separate and move to opposite poles. Telophase: Chromosomes uncoil, nuclear membrane reforms, nucleolus reappears. Cytokinesis: Cytoplasm divides, forming 2 daughter cells.
• Q: What is the significance of meiosis?
  Ans: Significance: (1) Reduces chromosome number to half — ensures constant chromosome number across generations after fertilisation. (2) Crossing over during prophase I causes genetic recombination — produces genetic variation. (3) Random assortment of chromosomes — further increases variation. (4) Essential for sexual reproduction and evolution.

Long Answer / Application Questions (4-6 Marks)

• Q: What is crossing over? When does it occur?
  Ans: Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes. It occurs during Prophase I of meiosis (specifically during pachytene stage). The point of crossing over is called chiasma. Significance: It produces new combinations of genes, increasing genetic diversity.

Exam Tips for This Chapter

• Revise all definitions and laws from Cell Division — they are commonly asked as 1-2 mark questions
• Practice diagrams related to Cell Division — neat labelled diagrams carry 2-3 marks
• For numericals, always show formula → substitution → answer with correct units
• Previous year analysis shows Cell Division carries 8-12 marks in the board exam