Cell Division: Easy Notes for Students | Class 11 Biology

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🔹 What is Cell Division?

Cell division is the process by which a parent cell divides into two or more new cells. It is essential for:

Growth of the organism

Repair of damaged tissues

Reproduction


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🔹 The Cell Cycle

The cell cycle is the sequence of events that a cell goes through before it divides. It has two main phases:

1. Interphase (Preparation stage):

G1 phase: Cell grows in size.

S phase: DNA gets duplicated.

G2 phase: Cell prepares proteins and organelles for division.



2. M phase (Division stage):

Includes mitosis or meiosis depending on the type of cell division.




👉 Remember: Interphase is the longest phase of the cell cycle.


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🔹 Types of Cell Division

There are two main types of cell division:

1. Mitosis – Equational Division

Mitosis occurs in somatic (body) cells and helps in growth and repair.

Prophase: Chromosomes condense, spindle forms.

Metaphase: Chromosomes line up at the equator.

Anaphase: Sister chromatids separate and move to opposite poles.

Telophase: Nuclear membrane reforms, cell divides.


👉 In mitosis, two identical daughter cells are formed.

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2. Meiosis – Reduction Division

Meiosis occurs in reproductive cells (gametes) and reduces the chromosome number by half.

Meiosis I: Homologous chromosomes separate.

Meiosis II: Sister chromatids separate.


👉 In meiosis, four non-identical haploid cells are produced. This is essential for sexual reproduction.

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🔹 Differences Between Mitosis and Meiosis

Feature Mitosis Meiosis

Type of cell Somatic cells Reproductive cells
Number of divisions One Two
Daughter cells 2 identical 4 different
Chromosome number Same as parent Half of parent


👉 Easy tip: Mitosis = Maintenance, Meiosis = Making gametes


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🔹 Why is Cell Division Important?

Growth of an organism

Repair of injuries

Reproduction

Genetic variation (through meiosis)


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🔹 NEET & CBSE Exam Tips

Always draw diagrams of mitosis and meiosis.

Practice previous year NEET questions from this chapter.

Remember key differences between mitosis and meiosis.

Focus on the phases of the cell cycle.


👉 Quick example NEET question:
Q: Which phase of the cell cycle is the longest?
Ans: Interphase.


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Final Words

Cell division may look tough, but if you understand the cell cycle, mitosis, and meiosis step by step, it becomes very easy. Use these class 11 biology notes for exam revision.

If you are preparing for NEET Biology, cell division is a high-scoring chapter with frequent MCQs. Keep practicing, and you will master it!

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