Chapter 2 Cell Division And Structure Of Chromosomes

Scope of Lesson: A clear understanding of the changes taking place at every stage. Discussion of mitosis in plants mitosis in animals to bring out their differences. In first meiotic division, only general idea of pairing and separation and chiasmata (details of the stages not required) Difference between mitosis and meiosis and significance of both.

1. Cell division: Introduction

  1. 1.1 Cell division

2. Cell cycle (diagram)

2.1 Interphase (diagram)
2.2 Mitotic phase: a) Karyokinesis b) Cytokinesis
2.3 Types of cell division-Categorised into two parts ie. :
  • A) Mitosis B) Meiosis
2.3.A Mitosis: The process of mitosis is studied in two parts:
  • a) Karyokinesis b) Cytokinesis
  1. Prophase (Diagram-early, mid, late prophase)
  2. Metaphase (Diagram- Metaphase)
  3. Anaphase (Diagram-early, late anaphase)
  4. Telophase (Diagram-early, late telophase)
2.4 Significance of mitosis:
  1. Maintenance of chromosome number (Genetic stability)
  2. Maintenance of cell size(difference in mitosis of plant and animal cell-table)
  3. Growth
  4. Replacement
  5. Repair
  6. Reproduction
  7. Regeneration
2.5 Meiosis: Stages in meiosis
2.5.A Meiosis-I(Reductional or Haploid division):
  • Meiosis-I is studied in two parts: A) Karyokinesis B) Cytokinesis
  • A) KARYOKINESIS: (division of nucleus)
  1. Prophase-I (Diagram-Mid-prophase-I)
  2. Metaphase-I (Diagram)
  3. Anaphase-I (Diagram)
  4. Telophase-I (Diagram)
2.5.B Meiosis-II (Equational Division):
  • This is also completed in two stages: A) Karyokinesis B) Cytokinesis
  1. Prophase-II (Diagram)
  2. Metaphase-II (Diagram)
  3. Anaphase-II(Diagram)
  4. Telophase-II (Diagram)
2.6 Significance of meiosis:
  1. Maintenance of chromosome number constant.
  2. Variations
  3. Evolution
  • (Differences between mitosis and meiosis-table)
2.7 Chromosomes:
  • a) Chromosome number (diploid no. of chromosomes in some species-table)
  • b) Structure of chromosome (Diagram)
  • c) Types of chromosomes:(Diagram for each)
  1. Metacentric
  2. Submetacentric
  3. Acrocentric
  4. Telocentric
  • d) Sex chromosomes and autosomes

3) Experiments

4) Key Points to remember: (Summary)

5) Key terms

6) BTT(Beyond the text): Extra Info.

7) Assignments:

  • 1) Objective type(1 mark each)
  • 2) Answer in one or two sentences (1 mark each)
  • 3) Give reasons (2 marks each)
  • 4) Short notes (2/3 marks each)
  • 5) Answer in detail (4/5 marks each)
  • 6) Board questions
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