Class 11 Cell Cycle and Cell Division NCERT PDF | Chapter 10 Biology

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Class 11 Cell Cycle and Cell Division NCERT PDF

Class 11 Cell Cycle and Cell Division NCERT PDF is an important study resource for Class 11 Biology students preparing for school examinations, CBSE examinations, and competitive exams such as NEET. This chapter explains the cell cycle, interphase, mitosis, meiosis, and the significance of cell division.

Class 11 Cell Cycle and Cell Division NCERT PDF

Download and study the official NCERT Class 11 Biology textbook containing Chapter 10: Cell Cycle and Cell Division.

Download NCERT Class 11 Biology PDF

Class 11 Biology Chapter 10: Cell Cycle and Cell Division

Cell division is one of the most important biological processes because it is essential for growth, development, repair and reproduction. The cell cycle describes the sequence of events through which a cell grows, duplicates its genetic material and divides into daughter cells.

What is the Cell Cycle?

The cell cycle is the series of events by which a cell grows, duplicates its DNA and eventually divides into daughter cells.

The cell cycle can broadly be divided into two major phases:

  1. Interphase
  2. M Phase

Interphase

Interphase is the period between two successive cell divisions. During interphase, the cell grows, carries out normal metabolic activities and prepares for cell division.

Interphase is divided into three stages:

  • G1 phase
  • S phase
  • G2 phase

G1 Phase

The G1 phase is the first phase of interphase. During this phase, the cell grows and synthesises RNA, proteins and other cellular components.

S Phase

The S phase is the phase in which DNA replication occurs. The genetic material is duplicated so that the daughter cells can receive genetic information.

G2 Phase

During the G2 phase, the cell continues to grow and prepares for mitotic division.

M Phase

The M phase represents the phase of actual cell division. It includes nuclear division followed by cytokinesis.

In mitosis, nuclear division is called karyokinesis, while division of the cytoplasm is called cytokinesis.

Mitosis

Mitosis is a type of cell division in which one parent cell produces two daughter cells that generally have the same chromosome number as the parent cell.

Stages of Mitosis

  1. Prophase
  2. Metaphase
  3. Anaphase
  4. Telophase

Prophase

During prophase, the chromatin condenses to form visible chromosomes. The mitotic spindle begins to form and the nucleolus gradually disappears.

Metaphase

During metaphase, chromosomes become arranged at the equatorial plane of the cell. Spindle fibres attach to the chromosomes at their centromeres through kinetochores.

Anaphase

During anaphase, sister chromatids separate and move towards opposite poles of the cell.

Telophase

During telophase, chromosomes reach the opposite poles and begin to decondense. Nuclear envelopes are formed around the daughter nuclei.

Cytokinesis

Cytokinesis is the division of the cytoplasm following nuclear division.

In animal cells, cytokinesis generally occurs by formation of a cleavage furrow. In plant cells, cytokinesis occurs through the formation of a cell plate.

Significance of Mitosis

  • Helps in growth and development.
  • Helps in repair and replacement of damaged cells.
  • Maintains the chromosome number in daughter cells.
  • Plays an important role in asexual reproduction in many organisms.

Meiosis

Meiosis is a specialised type of cell division associated with the formation of haploid cells. It involves two successive divisions after a single round of DNA replication.

These divisions are known as:

  1. Meiosis I
  2. Meiosis II

Meiosis I

Meiosis I is also called the reduction division because the chromosome number is reduced to half.

Stages of Meiosis I

  1. Prophase I
  2. Metaphase I
  3. Anaphase I
  4. Telophase I

Prophase I

Prophase I is a lengthy and complex stage of meiosis. It is further divided into:

  1. Leptotene
  2. Zygotene
  3. Pachytene
  4. Diplotene
  5. Diakinesis

Crossing Over

Crossing over occurs during pachytene of Prophase I. It involves the exchange of genetic material between non-sister chromatids of homologous chromosomes and contributes to genetic variation.

Metaphase I

During metaphase I, homologous chromosome pairs arrange themselves at the equatorial plane of the cell.

Anaphase I

During anaphase I, homologous chromosomes separate and move towards opposite poles. The sister chromatids remain together.

Telophase I

During telophase I, chromosomes reach the poles and nuclear membranes may reform. Cytokinesis may follow.

Meiosis II

Meiosis II resembles mitotic division. It occurs without another round of DNA replication.

The stages are:

  1. Prophase II
  2. Metaphase II
  3. Anaphase II
  4. Telophase II

Significance of Meiosis

  • Produces haploid cells.
  • Maintains the chromosome number across generations in sexually reproducing organisms.
  • Creates genetic variation through crossing over and independent assortment.
  • Is important in sexual reproduction.

Mitosis vs Meiosis

Feature Mitosis Meiosis
Number of divisions One Two
Daughter cells Usually two Usually four
Chromosome number Maintained Reduced by half
Crossing over Generally absent Occurs during Prophase I
Main role Growth, repair and asexual reproduction Sexual reproduction and genetic variation

Important NCERT Topics for Class 11

  • Cell cycle
  • Interphase
  • G1, S and G2 phases
  • M phase
  • Mitosis
  • Stages of mitosis
  • Cytokinesis
  • Meiosis
  • Meiosis I
  • Meiosis II
  • Prophase I and its sub-stages
  • Crossing over
  • Significance of mitosis and meiosis

Class 11 Cell Cycle and Cell Division NCERT PDF for NEET

Students preparing for NEET should study Cell Cycle and Cell Division carefully because questions can test individual stages, chromosome behaviour, crossing over, cytokinesis and differences between mitosis and meiosis.

For NCERT-based preparation, students should read the official textbook carefully and revise important diagrams and terminology.

NEET Tip: Pay special attention to Prophase I of meiosis, the sequence of mitotic stages, chromosome movement during anaphase, and the difference between meiosis I and meiosis II.

Download Class 11 Cell Cycle and Cell Division NCERT PDF

The official NCERT Class 11 Biology textbook contains Chapter 10: Cell Cycle and Cell Division. NCERT's textbook listing identifies Chapter 10 under Unit III, “Cell: Structure and Functions.”

Click Here to Download the Official NCERT Class 11 Biology PDF

Conclusion

Class 11 Cell Cycle and Cell Division NCERT PDF is a useful resource for understanding one of the most important chapters of Class 11 Biology. Students should combine NCERT reading with regular revision, diagrams, comparison tables and NCERT-based questions for effective preparation.

Study NCERT. Revise repeatedly. Focus on concepts and diagrams.