# Cell Cycle and Cell Division, Class 11 Biology | SwaVid Cell Cycle and Cell Division, NCERT Class 11 Biology: notes with key ideas, key terms, common mistakes and 3 quick checks with worked answers. Canonical: https://www.swavid.com/cbse/class-11/biology/chapter/cell-cycle-and-cell-division Source: https://www.swavid.com/cbse/class-11/biology/chapter/cell-cycle-and-cell-division # Cell Cycle and Cell Division ## Key terms ## Key ideas ## Common mistakes ## Quick checks ## Keep going ## Questions parents ask ## Class 11 Biology on SwaVid ### Phases of cell cycle ### Interphase stages ### Mitosis and its stages ### Cytokinesis ### Meiosis I and reduction ### Meiosis II and significance ### Next chapter ### Related chapter ### Related chapter ### Related chapter ### All chapters SwaVid › CBSE › Class 11 › Biology › Cell Cycle and Cell Division Notes written by SwaVid from the NCERT textbook. Class 11 Biology, Chapter 10. Key ideas, formulas and common mistakes. CBSE prints 15 marks for Unit III, not for this chapter alone. Short answer. This chapter describes the sequence of events by which a cell duplicates its genome, synthesises other constituents, and divides into daughter cells. It explains the phases of interphase, mitosis, and meiosis along with their biological significance in growth and reproduction. Source: NCERT Biology (Reprint 2026-27) , Chapter 10, Cell Cycle and Cell Division The cell cycle comprises interphase and M Phase. Interphase represents the resting phase where the cell prepares for division, lasting more than 95 percent of the cycle duration. M Phase is the stage of actual division. Interphase is divided into G1 phase, S phase, and G2 phase. DNA replication and duplication of centrioles occur during S phase, while cell growth and protein synthesis occur across G1 and G2 phases. Cells that do not divide exit G1 into a quiescent stage called G0. Mitosis is equational division divided into prophase, metaphase, anaphase, and telophase. Metaphase is characterised by chromosomes aligning at the equatorial plate, while anaphase involves splitting of centromeres and movement of chromatids to opposite poles. Nuclear division (karyokinesis) is followed by division of cytoplasm (cytokinesis). Animal cells divide by furrowing of the plasma membrane, whereas plant cells divide from the centre outward by forming a cell plate. Meiosis reduces chromosome number by half to produce haploid gametes. Prophase I has five sub-stages: leptotene, zygotene, pachytene, diplotene, and diakinesis. Crossing over and genetic recombination occur during pachytene. Meiosis II resembles a normal mitosis and separates sister chromatids. It results in four haploid daughter cells from one diploid parent cell, conserving chromosome number across generations and generating genetic variations. Try each question first. Then tap it to see the answer. During S phase, DNA replication doubles the total amount of DNA: 2C × 2 = 4C. The number of chromosomes does not change during S phase: 16 chromosomes remain 16. DNA content is 4C and chromosome number is 16 Meiosis I is a reductional division: 24 ÷ 2 = 12 chromosomes per cell. Meiosis II is an equational division for haploid cells: chromosome number stays at 12. 12 chromosomes at the end of meiosis I and 12 chromosomes at the end of meiosis II Interphase duration = Total duration - M phase duration = 24 - 1 = 23 hours. Percentage = (23 / 24) × 100 ≈ 95.83%. About 96 percent (or greater than 95 percent) Photosynthesis in Higher Plants . Cell: The Unit of Life . Biomolecules . Plant Growth and Development . The 19 chapters of Class 11 Biology . CBSE does not give marks to one chapter. It prints 15 marks for Unit III, Cell: Structure and Function, which includes Cell Cycle and Cell Division. No. They are written by SwaVid from the NCERT textbook. The CBSE curriculum is the reference for what is assessed. Photosynthesis in Higher Plants. SwaVid is an AI tutor for Indian students in Classes 6 to 12. It finds the earlier ideas a child missed, then teaches today’s chapter. Start free to see how it works. - Ch 10 NCERT book - 15 marks, Unit III - 3 quick checks - Thinking chromosome number doubles during the S phase . Only the amount of DNA doubles (from 2C to 4C) during S phase. The chromosome number remains the same (2n). - Confusing anaphase of mitosis with anaphase I of meiosis . Centromeres split and sister chromatids separate in mitotic anaphase. In anaphase I of meiosis, homologous chromosomes separate while sister chromatids remain attached at their centromeres. - Mixing up the order of the five stages of prophase I . Remember the correct sequence: leptotene, zygotene, pachytene, diplotene, and diakinesis. - Assuming interkinesis includes DNA replication . Interkinesis is a short-lived stage between meiosis I and meiosis II. There is no DNA replication during interkinesis. ## Key Links - [CBSE](https://www.swavid.com/cbse) - [Class 11](https://www.swavid.com/cbse/class-11) - [Biology](https://www.swavid.com/cbse/class-11/biology/chapters) - [Start free →](https://www.swavid.com/signup) - [All 19 chapters](https://www.swavid.com/cbse/class-11/biology/chapters) - [NCERT Biology (Reprint 2026-27)](https://ncert.nic.in/textbook.php) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/photosynthesis-in-higher-plants) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/cell-the-unit-of-life) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/biomolecules) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/plant-growth-and-development) - [Class 11 Biology](https://www.swavid.com/cbse/class-11/biology/chapters) - [Start free →](https://www.swavid.com/signup)