Skip to content
← Biology

Biology · Class 11 Science

Ch 10Cell Cycle and Cell Division — Class 11 Biology, concept-first.

Every cell that is going to divide does not simply split in two at random. It passes through an orderly, tightly regulated sequence of events -- growing to an appropriate size, copying its entire genetic material exactly once, checking that the copy is correct, and only then physically dividing into two daughter cells…

32

Q&A

8

Concepts

~4m

Unit weightage

Start learning — read this chapter →

Key concepts

Hover a concept to preview it and jump to its most relevant Q&A.

Cell Cycle

The cell cycle is the ordered series of events by which a cell grows and divides to produce two new cells, first described by Prevost and Dumans in 1824.

Most relevant Q&A

Start with this concept →

Chapter contents

The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.

10.1

The Cell Cycle: Definition and Phases

Every cell that is going to divide does not simply split in two at random. It passes through an orderly, tightly regulated sequence of events -- growing to an appropriate size, copying its entire gene…

10.2

Interphase: G1, S and G2 Phases

Interphase, the interval between one M phase and the next, is not a single uniform state but is itself divided into three successive sub-phases, conventionally labelled G1, S and G2, each dedicated to…

10.3

M Phase: The Stages of Mitosis

M phase, the mitotic phase of the cell cycle, is the visibly dramatic interval in which the duplicated genetic material assembled during interphase is precisely divided between two daughter nuclei --…

10.4

Significance of Mitosis

Mitosis is frequently described as an 'equational division' because the number of chromosomes in each of the two daughter cells it produces is exactly the same as the number in the original parent cel…

10.5

Meiosis I

Meiosis is the special type of cell division, restricted to the germ cells that give rise to gametes, in which a single diploid parent cell ultimately produces four haploid daughter cells through two…

10.6

Meiosis II

Meiosis II is the second of the two successive divisions of meiosis, and it follows meiosis I directly, without any intervening round of DNA replication -- the two haploid cells produced by meiosis I…

10.7

Significance of Meiosis

Meiosis is not merely a variant form of cell division; it is a biological necessity for every organism that reproduces sexually, and its significance rests on two distinct, equally essential consequen…

10.8

Mitosis and Meiosis Compared

Mitosis and meiosis are both forms of nuclear division that rely on the same essential machinery -- condensed chromosomes, a spindle apparatus built of microtubules, and the orderly, stage-by-stage mo…

Summary

The cell cycle is the ordered, repeating sequence of growth, DNA replication and division through which a cell passes, divided into a long interphase (itself made up of the G1, S and G2 sub-phases, oc…

Very Short Answer Questions

+Show 8 questions8 questions
  1. Q11Define the cell cycle in one sentence.Free
  2. Q12Name the phase of interphase, coming after DNA replication is complete, during which the cell synthesises the proteins needed to build the m…Free
  3. Q13State one visible structural change undergone by chromatin during prophase of mitosis.Free
  4. Q14Name the imaginary plane, located midway between the two spindle poles, at which chromosomes become aligned during metaphase.Preview
  5. Q15State, in one line, why mitosis is often described as an 'equational division.'Preview
  6. Q16Name, in correct order, the five successive sub-stages into which prophase I of meiosis I is divided.Preview
  7. Q17Define chiasmata, and name the sub-stage of prophase I at which they first become visible.Preview
  8. Q18Name the short-lived stage that intervenes between the completion of meiosis I and the start of meiosis II, during which no further DNA repl…Preview

Short Answer Questions

+Show 8 questions8 questions
  1. Q19Describe the three sequential phases of interphase -- G1, S and G2 -- briefly stating the principal event that characterises each.Free
  2. Q20Describe the sequence of events that occur during anaphase and telophase of mitosis.Free
  3. Q21Explain why mitosis is essential for the growth and repair of tissues in a multicellular organism, and why it is necessary for the two daugh…Free
  4. Q22Distinguish between mitosis and meiosis on the basis of (i) the number of successive divisions involved, (ii) the number of daughter cells p…Preview
  5. Q23Describe the principal cytological events that occur during the zygotene and pachytene sub-stages of prophase I of meiosis I.Preview
  6. Q24Explain how independent assortment of homologous chromosome pairs during meiosis I contributes to genetic variation among the gametes produc…Preview
  7. Q25Describe the process of cytokinesis that follows karyokinesis in mitosis, and state one way in which cytokinesis in a plant cell differs fro…Preview
  8. Q26Explain why meiosis is essential for organisms that reproduce sexually, with reference to the maintenance of a constant chromosome number ac…Preview

Long Answer Questions

+Show 6 questions6 questions
  1. Q27Give a detailed, stage-by-stage account of the events of mitosis -- prophase, metaphase, anaphase and telophase -- explaining at each stage…Free
  2. Q28Describe in detail the five sub-stages of prophase I of meiosis I -- leptotene, zygotene, pachytene, diplotene and diakinesis -- explaining…Free
  3. Q29Give a detailed account of the events of meiosis II, and explain why the overall two-division process of meiosis is described as a 'reductio…Preview
  4. Q30Discuss in detail the significance of meiosis, covering both the halving of the chromosome number and the generation of genetic variation th…Preview
  5. Q31Give a comprehensive comparative account of mitosis and meiosis, covering where each occurs, the number of divisions involved, whether homol…Preview
  6. Q32Describe the complete cell cycle, covering interphase (the G1, S and G2 phases) and M phase (karyokinesis followed by cytokinesis), and expl…Preview

More questions

+Show 10 questions10 questions
  1. Q1Interphase, during which a cell grows, duplicates its DNA and prepares its organelles without yet visibly dividing, typically occupies what…Free
  2. Q2During which phase of interphase does DNA replication take place, so that the amount of DNA per cell doubles before the cell divides? (a) G1…Free
  3. Q3In an animal cell, duplication of the centriole occurs during the same phase of the cell cycle as: (a) Nuclear envelope breakdown (b) DNA re…Free
  4. Q4Certain cells, such as mature neurons and cardiac muscle cells, exit the active cell cycle after completing one round of mitosis and remain…Preview
  5. Q5At which stage of mitosis does the nuclear envelope begin to disintegrate and the mitotic spindle begin to assemble, while chromatin progres…Preview
  6. Q6At which stage of mitosis do all the chromosomes become arranged at the equatorial plate (metaphase plate), with the kinetochores of sister…Preview
  7. Q7The simultaneous splitting of the centromere joining each pair of sister chromatids, followed by their movement toward opposite poles of the…Preview
  8. Q8The pairing of homologous chromosomes to form a bivalent (tetrad), a process seen in meiosis but never in mitosis, is called: (a) Synapsis (…Preview
  9. Q9The reciprocal exchange of segments of genetic material between non-sister chromatids of a bivalent, a major source of new genetic combinati…Preview
  10. Q10Which of the following is NOT a recognised significance of meiosis? (a) It halves the chromosome number, keeping the chromosome number const…Preview