NCERT Class 11 Biology Biology: Chapter 10 — Cell Cycle and Cell Division
This chapter introduces the fundamental biological process of the cell cycle and cell division. It explains that all organisms, from single cells to complex multicellular ones, originate from a single cell and grow through cell division. The chapter details the cell cycle as a sequence of events where a cell duplicates its genome, synthesizes other constituents, and divides into two daughter cells. It highlights that while cell growth is continuous, DNA synthesis occurs at a specific stage. The cell cycle is divided into two main phases: Interphase (G1, S, G2 phases) and M Phase (Mitosis). Interphase involves cell growth and DNA replication, preparing the cell for division. The M phase is when actual cell division occurs. The chapter emphasizes the coordinated nature of these processes to ensure accurate genome distribution to daughter cells, crucial for growth and reproduction in all living organisms.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 11 |
| Subject | Biology |
| Book | Biology |
| Chapter | Chapter 10 — Cell Cycle and Cell Division |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 4 minutes |
| Word count | 742 |
Learning outcomes
- Understand the importance of cell division for growth and reproduction.
- Describe the sequence of events in a cell cycle.
- Differentiate between Interphase and M Phase.
- Identify the sub-phases of Interphase (G1, S, G2).
- Explain the significance of DNA replication during the S phase.
Vocabulary
| Word | Meaning |
|---|---|
| Cell Cycle | The sequence of events by which a cell duplicates its genome, synthesizes other constituents, and eventually divides into two daughter cells. |
| Interphase | The phase of the cell cycle between two successive M phases, during which the cell prepares for division. |
| M Phase | The phase of the cell cycle when actual cell division (mitosis) occurs. |
| G1 phase | Gap 1 phase, the interval between mitosis and initiation of DNA replication, where the cell grows. |
| S phase | Synthesis phase, during which DNA synthesis or replication takes place. |
| G2 phase | Gap 2 phase, where proteins are synthesized in preparation for mitosis and cell growth continues. |
| Karyokinesis | Nuclear division, the separation of daughter chromosomes. |
| Cytokinesis | Division of the cytoplasm. |
| Genome | The complete set of genetic material present in a cell or organism. |
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Practice questions
- What is the cell cycle? Answer: The cell cycle is the sequence of events by which a cell duplicates its genome, synthesizes other constituents, and eventually divides into two daughter cells.
- Name the two main phases of the cell cycle. Answer: The two main phases are Interphase and M Phase.
- What happens during the S phase of the cell cycle? Answer: During the S phase, DNA synthesis or replication takes place, and the amount of DNA per cell doubles.
- What is the significance of the G1 phase? Answer: During the G1 phase, the cell is metabolically active, grows, and prepares for DNA replication.
- Define Karyokinesis and Cytokinesis. Answer: Karyokinesis is the division of the nucleus, and Cytokinesis is the division of the cytoplasm.
Frequently asked questions
What is the average duration of the cell cycle for a human cell?
The average duration of the cell cycle for a human cell is approximately 24 hours.
How long does cell division proper last in a human cell?
Cell division proper (M Phase) lasts for only about an hour in a 24-hour cell cycle.
Does the chromosome number change during the S phase?
No, the chromosome number remains the same (e.g., 2n) even after DNA replication in the S phase; only the amount of DNA doubles.
What is the role of the G2 phase?
In the G2 phase, proteins are synthesized in preparation for mitosis, and cell growth continues.
Can the cell cycle duration vary?
Yes, the duration of the cell cycle can vary significantly from organism to organism and from cell type to cell type.
What happens during cytokinesis?
Cytokinesis is the division of the cytoplasm, which usually follows nuclear division (karyokinesis) and ends the M phase.
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NCERT Class 11 Biology — Biology — Chapter 10 — Cell Cycle and Cell Division. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.