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REET L2 (Maths-Science) · Science

Cell Division — REET Notes

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Cell division is a foundational topic in the Science portion of REET Level 2, and the stages, purpose, and differences between mitosis and meiosis are what get asked most often. This page walks through both types of division comparatively, following the syllabus, so there's no confusion in the exam.

  • 0 questions in REET 2024
  • Class 9-10 level content
  • 7 min read
Verified 17 September 2026 · Source: NCERT Science Textbook (Class 9-10)

How this topic is asked in REET

To be upfront: no direct question on cell division appeared in the REET 2024 paper — this topic saw zero (0) questions in 2024. So this entire page is built on the language of the official REET Level 2 (Maths-Science) syllabus, not on any past question. In the syllabus, this topic falls under the 'Cell' section, so there's a real chance that upcoming exams carry a direct one-line MCQ on the stages of mitosis and meiosis, the change in chromosome number, and the difference between the two.

Why the cell cycle and cell division matter

Every living cell goes through a defined cycle called the cell cycle. It has two main parts — interphase, during which the cell grows and replicates its DNA, and the M-phase, during which actual cell division happens. Interphase is further divided into the G1, S, and G2 sub-phases; DNA replication happens in the S-phase.

Cell division is essential for living organisms because it drives growth, repairs worn-out or damaged cells, and produces gametes (reproductive cells), making reproduction possible. Ordinary body cells (somatic cells) divide by mitosis, while meiosis is needed specifically to produce reproductive cells.

Mitosis

Mitosis happens in somatic (body) cells and produces two daughter cells from one parent cell — daughter cells that are genetically identical to the parent, with the same chromosome number as the parent (diploid to diploid). It is completed in four main stages, useful to remember in order — Prophase, Metaphase, Anaphase, and Telophase, or P-M-A-T for short.

In prophase, the chromosomes start becoming thick and visible, and the nuclear membrane begins breaking down. In metaphase, all the chromosomes line up at the cell's equatorial plane (the spindle equator). In anaphase, the two chromatids of each chromosome separate and are pulled toward opposite poles. In telophase, a new nuclear membrane forms, and finally cytokinesis (division of the cytoplasm) produces two complete daughter cells. This same division drives growth and repair processes like wound healing in the body.

Meiosis

Meiosis happens only in reproductive cells (germ-mother cells), and its purpose is to produce gametes (such as sperm and egg cells). One parent cell goes through two successive divisions (Meiosis-I and Meiosis-II), ending up with four daughter cells in total, and each daughter cell has half (haploid) the chromosome number of the parent cell.

Meiosis-I is called a reductional division because this is where the chromosome number is halved — homologous chromosomes pair up and then separate. During Prophase-I of this stage, crossing over takes place, in which genetic material is exchanged between homologous chromosomes — this is the single biggest source of genetic variation in the next generation. Meiosis-II is roughly similar to mitosis, in which the chromatids separate. This is why meiosis is necessary for both reproduction and genetic variation.

Mitosis vs Meiosis — key differences

Mitosis

Where it happensSomatic (body) cells

Number of divisionsOnce

Number of daughter cells2

Chromosome numberSame as the parent cell (diploid)

Genetic variationNo (all identical)

Main purposeGrowth and repair

Meiosis

Where it happensReproductive cells

Number of divisionsTwice (Meiosis-I and II)

Number of daughter cells4

Chromosome numberHalf the parent cell's (haploid)

Genetic variationYes (from crossing over)

Main purposeReproduction (gamete formation)

Most REET questions on this topic come in exactly this comparative form.

Quick facts worth remembering

Chromosome number in humans
46 (23 pairs) — in diploid cells
Chromosome number in gametes (sperm/egg)
23 — haploid, because of meiosis
When crossing over happens
In Prophase-I of Meiosis-I
When DNA replication happens
In the S-phase of interphase, before division

Biological significance and real-life examples of cell division

Cell division isn't just a textbook concept — it's tied to everyday events in life. When there's a wound on the skin, the cells at the wound's edges divide rapidly by mitosis to produce new cells and heal the wound. In plants, continuous mitotic division at the growing tips of roots and stems (meristematic regions) is exactly what makes the plant grow taller and thicker.

On the other hand, if cell division becomes uncontrolled and cells keep dividing repeatedly without any check, abnormal tissue growth (a tumour) can form — this is the basic scientific understanding behind cancer. This makes it clear how important it is for cell division to happen at the right time and in a controlled way for the body to stay healthy.

How to teach this to students

Classroom activity

Have students build 'chromosome models' out of different coloured clay or wool threads, and get them to pull the models apart by hand to show how mitosis forms 2 daughter groups while meiosis forms 4.

Teaching aids

Put up a large chart or flip-chart of the four P-M-A-T stages in class; where possible, showing a permanent onion-root-tip slide under a microscope works well at Class 9-10 level.

Common misconception

Students often assume the chromosome number in meiosis also stays equal to the parent cell, or they mix up which type of division produces more daughter cells. Repeating the comparative table clears this up.

Assessment idea

Give students an unlabeled P-M-A-T diagram and ask them to identify and sequence the stages, and have them write down the chromosome number of the parent versus the daughter cell in one line.

Memory trick / exam tip

'Meiosis means half' — in meiosis the chromosome number is always halved and 4 daughter cells form, while in mitosis the number stays the same as the parent cell and only 2 daughter cells form. The moment you see the phrase 'chromosome number halved' or '4 daughter cells' in the exam, go straight for meiosis.

Practice questions

Question 1

As a result of mitosis, how many daughter cells are formed from one parent cell?

  1. Aएक
  2. Bदो
  3. Cतीन
  4. Dचार

Explanation

Mitosis produces two daughter cells from one parent cell, and these daughter cells match the parent cell in chromosome number and genetic makeup.

Question 2

At the end of meiosis, how does the chromosome number of daughter cells compare to that of the parent cell?

  1. Aदोगुनी
  2. Bबराबर
  3. Cआधी
  4. Dतीन गुनी

Explanation

In meiosis, the chromosome number is halved (haploid), so that after fertilisation, the normal diploid number is restored in the offspring.

Question 3

What is the correct sequence of the stages of mitosis?

  1. Aमेटाफेज़ - प्रोफेज़ - एनाफेज़ - टीलोफेज़
  2. Bप्रोफेज़ - मेटाफेज़ - एनाफेज़ - टीलोफेज़
  3. Cटीलोफेज़ - एनाफेज़ - मेटाफेज़ - प्रोफेज़
  4. Dप्रोफेज़ - एनाफेज़ - मेटाफेज़ - टीलोफेज़

Explanation

The correct order of mitosis is P-M-A-T — Prophase → Metaphase → Anaphase → Telophase.

Question 4

Crossing over, which is a major cause of genetic variation, occurs during which stage?

  1. Aसमसूत्री विभाजन की मेटाफेज़
  2. Bअर्धसूत्री विभाजन की प्रोफेज़-I
  3. Cअर्धसूत्री विभाजन की एनाफेज़-II
  4. Dइंटरफेज़ की G1 प्रावस्था

Explanation

Crossing over happens between homologous chromosomes during Prophase-I of meiosis (Meiosis-I), and it's what brings new genetic variation to the offspring.

Question 5

During which phase of the cell cycle does DNA replication occur?

  1. AG1 प्रावस्था
  2. BS-प्रावस्था
  3. CG2 प्रावस्था
  4. DM-प्रावस्था

Explanation

DNA replication happens during the S-phase (Synthesis phase) of interphase, after which the cell divides during the M-phase.

Question 6

Why is meiosis called a reductional division?

  1. Aक्योंकि इसमें कोशिका का आकार घट जाता है
  2. Bक्योंकि इसमें गुणसूत्रों की संख्या आधी हो जाती है
  3. Cक्योंकि इसमें केवल एक संतति कोशिका बनती है
  4. Dक्योंकि इसमें कोशिकाद्रव्य विभाजित नहीं होता

Explanation

In Meiosis-I, homologous chromosomes separate, taking the chromosome number from diploid down to haploid — which is why it's called a reductional division.

Question 7

Which of the following statements is correct about the division occurring in somatic cells?

  1. Aयह अर्धसूत्री विभाजन है और युग्मक बनाता है
  2. Bयह समसूत्री विभाजन है और वृद्धि व मरम्मत करता है
  3. Cइसमें गुणसूत्र संख्या आधी हो जाती है
  4. Dइसमें चार संतति कोशिकाएँ बनती हैं

Explanation

Somatic (body) cells divide by mitosis, which is responsible for the body's growth and for repairing damaged tissue.

Question 8

A teacher has students build thread-and-clay models to show chromosome separation while teaching cell division. This activity mainly serves which teaching objective?

  1. Aकेवल परीक्षा के लिए रटना
  2. Bअमूर्त प्रक्रिया को मूर्त रूप में समझाना
  3. Cसमय की बचत करना
  4. Dकक्षा को व्यस्त रखना मात्र

Explanation

Showing an abstract, microscopic process like cell division through models and hands-on activity gives students a direct, concrete experience that helps clarify the concept.

Question 9

In which stage of mitosis do chromosomes arrange themselves at the equatorial plane of the spindle?

  1. Aप्रोफेज़
  2. Bमेटाफेज़
  3. Cएनाफेज़
  4. Dटीलोफेज़

Explanation

In metaphase, all the chromosomes arrange themselves in a single line at the cell's equatorial plane with the help of spindle fibres — this is the defining feature of this stage.

Question 10

Regarding the biological significance of meiosis, which of the following statements is the most appropriate?

  1. Aयह केवल कोशिका की संख्या बढ़ाता है
  2. Bयह पीढ़ी-दर-पीढ़ी गुणसूत्र संख्या स्थिर रखने के साथ आनुवंशिक विविधता भी लाता है
  3. Cयह केवल पौधों में होता है
  4. Dइसमें कोई आनुवंशिक परिवर्तन नहीं होता

Explanation

Meiosis halves the chromosome number in gametes so the normal number is restored after fertilisation, and crossing over during meiosis also produces genetic variation.

Frequently asked questions

Which cells does meiosis happen in?+

Meiosis happens only in reproductive cells (germ-mother cells), producing gametes like sperm and egg cells.

How many chromosomes do human somatic cells have?+

Normal human somatic cells have 46 chromosomes (23 pairs); this number drops to 23 in gametes after meiosis.

What's the main difference between mitosis and meiosis?+

Mitosis produces 2 identical daughter cells with the same chromosome number, while meiosis produces 4 daughter cells with half the chromosome number.

How many REET questions have come from cell division?+

No direct question came from this topic in REET 2024, but since it's part of the 'Cell' section, it stays important for upcoming exams.

What is crossing over?+

Crossing over is the exchange of genetic material between homologous chromosomes during Prophase-I of meiosis, and it's what brings genetic variation to offspring.

Read next

Cell Structure

REET notes: Cell Structure — read this before this topic.

Plant Structure and Function

REET notes: Plant Structure and Function — read this after this topic.

REET Syllabus

See the full official REET Level 1 and Level 2 syllabus, subject by subject.

REET 2024 Solved Paper

All REET 2024 questions with solutions and explanations in Hindi.

Official Sources

  1. NCERT Science Textbook (Class 9-10)
  2. NCERT Science Textbook (Class 6-8)

Change Log

  • 17 September 2026 — English page published — mirrors the fact-checked Hindi page, independently bilingual-accuracy checked