NEET Biology Cell Division 2027: Cell Cycle, Mitosis, Meiosis — Complete Chapter Notes and MCQs - NEET Gurukul

NEET Biology Cell Division 2027: Cell Cycle, Mitosis, Meiosis — Complete Chapter Notes and MCQs

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Last Updated: April 2026

Cell Division is one of the most consistently tested topics in NEET Biology, appearing in almost every paper with 2–4 questions. This chapter from NCERT Class 11 (Chapter 10: Cell Cycle and Cell Division) covers the fundamental process by which cells replicate — essential for understanding genetics, reproduction, and cancer biology.

In NEET 2024 and 2025, cell division contributed 3 questions each year. Master this chapter thoroughly and you’re guaranteed marks.

Cell Cycle — Overview

The cell cycle is the sequence of events a cell goes through from its formation to its division into two daughter cells. It has two major phases:

  1. Interphase (I-Phase): The preparatory phase — cell grows and duplicates its DNA
  2. M-Phase (Mitotic Phase): The actual division of the cell

Interphase — Sub-phases

Sub-phase Full Name What Happens Duration (human cell)
G₁ Phase First Gap Phase Cell growth; protein synthesis; organelle duplication ~12 hours
S Phase Synthesis Phase DNA replication; chromosome number doubles (but cell stays diploid) ~8 hours
G₂ Phase Second Gap Phase Further growth; synthesis of spindle proteins; final preparation ~4 hours

Key NEET Point: Interphase = G₁ + S + G₂ (NOT a resting phase — it is the most metabolically active phase)

Mitosis — Equational Division

Mitosis produces two genetically identical daughter cells, each with the same chromosome number as the parent. It occurs in somatic (body) cells for growth and repair.

Phases of Mitosis — Quick Reference

Phase Key Events NEET Trigger Words
Prophase Chromatin condenses to chromosomes; nucleolus disappears; spindle forms; nuclear envelope breaks down Longest phase; chromatin → chromosomes; spindle appears
Metaphase Chromosomes align at metaphase plate (equatorial plane); centromeres attach to spindle fibres Metaphase plate; best stage to count chromosomes; centromere
Anaphase Centromeres split; sister chromatids separate and move to opposite poles; cell elongates Shortest phase; chromatids separate; V-shape movement
Telophase Chromosomes reach poles; decondense; nuclear envelope reforms; nucleolus reappears Reverse of prophase; two nuclei form
Cytokinesis Cytoplasm divides: cleavage furrow in animals; cell plate in plants Animal = furrow inward; Plant = phragmoplast + cell plate

Meiosis — Reductional Division

Meiosis occurs in reproductive cells (germ cells) to produce gametes. It reduces chromosome number by half (2n → n) and introduces genetic variation through crossing over.

Meiosis I — The Reductional Division

Sub-phase Key Events Important NEET Fact
Leptotene Chromosomes begin to condense; bead-like chromomeres visible First sub-stage of Prophase I
Zygotene Homologous chromosomes pair up (synapsis); synaptonemal complex forms Synapsis occurs here; bivalents formed
Pachytene Crossing over occurs at chiasmata; genetic recombination Most important sub-stage — NEET favourite
Diplotene Synaptonemal complex dissolves; chiasmata visible; chromosomes partially separate Chiasmata visible; lampbrush chromosomes in amphibians
Diakinesis Chromosomes maximally condensed; nuclear envelope breaks; spindle forms End of Prophase I; chiasmata move toward ends (terminalization)

Meiosis II — The Equational Division

Meiosis II is similar to mitosis — it separates sister chromatids. The result is 4 haploid cells (gametes) from one original diploid cell.

Mitosis vs Meiosis — Key Differences for NEET

Feature Mitosis Meiosis
Occurs in Somatic cells Germ cells / reproductive cells
Number of divisions 1 2 (Meiosis I + Meiosis II)
Daughter cells produced 2 4
Chromosome number Same as parent (2n) Half of parent (n)
Genetic variation No (identical clones) Yes (crossing over)
Crossing over Does not occur Occurs in Prophase I (Pachytene)
Purpose Growth, repair, asexual reproduction Sexual reproduction, gamete formation
Bivalent formation No Yes (in Zygotene)

Important Facts — NEET Exam Traps

  • Interphase is NOT the resting phase — active synthesis occurs throughout
  • DNA replication occurs in S phase of Interphase (not in Prophase)
  • Crossing over is a feature of Prophase I (Pachytene) — not Metaphase or Anaphase
  • In animals, cytokinesis occurs by cleavage furrow (inward pinching)
  • In plants, cytokinesis occurs by phragmoplast forming a cell plate (outward growth)
  • Colchicine stops cell division at Metaphase by dissolving spindle fibres
  • Meiosis is also called reductional division; Mitosis is equational division

NEET MCQ Practice: Cell Division

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Frequently Asked Questions — Cell Division NEET

How many questions come from Cell Division in NEET?

Cell Division typically contributes 2–4 questions in NEET. In NEET 2024 and 2025, 3 questions each came from this chapter. Focus on Prophase I sub-stages (especially Pachytene for crossing over), cytokinesis differences between plant and animal cells, and the comparison between mitosis and meiosis.

What is the difference between mitosis and meiosis in one line?

Mitosis produces 2 genetically identical diploid (2n) daughter cells for growth and repair; meiosis produces 4 genetically diverse haploid (n) daughter cells (gametes) for sexual reproduction.

Where does crossing over occur?

Crossing over occurs during Pachytene — the third sub-stage of Prophase I of Meiosis. The points where chromosomes cross and exchange genetic material are called chiasmata (singular: chiasma). This process creates genetic recombination and is the basis of genetic diversity.

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