NCERT Solutions for Class 11 Biology Chapter 10 Cell Cycle and Cell Division

 

NCERT solutions for class 11 biology chapter 10 cell cycle and cell division: Are you aware of this fact, that all organisms, even the largest or the smallest, start their life from a single cell? You may wonder how from a single cell they form such large organisms. Solutions for NCERT class 11 biology chapter 10 cell cycle and cell division contain solutions which comprise of an excellent explanation of all the questions which are based on cell division and the different cycles of the cell. You will learn that growth and reproduction are characteristics of cells, indeed of all living organisms. NCERT solutions for class 11 biology chapter 10 cell cycle and cell division will provide you all the answers to those questions which are mentioned in this chapter. You will be surprised by knowing that all the cells reproduce by dividing into two, with each parental cell giving rise to two daughter cells each time they divide and these newly formed daughter cells can themselves grow and divide, giving rise to a new cell population that is formed by the growth and division of a single parental cell and its progeny. If you are looking for an answer from any other chapter even from any other class then go with NCERT Solutions, there you will get all the answers of NCERT easily.

Here are the important topics of CBSE NCERT solutions for class 11 biology chapter 10 cell cycle and cell division given below:

10.1 Cell Cycle

  • 10.1.1 Phases of Cell Cycle

10.2 M Phase

  • 10.2.1 Prophase
  • 10.2.2 Metaphase
  • 10.2.3 Anaphase
  • 10.2.4 Telophase
  • 10.2.5 Cytokinesis

10.3 Significance of Mitosis

10.4 Meiosis

  • 10.4.1 Meiosis I
  • 10.4.2 Meiosis II

10.5 Significance of Meiosis

Cell division is a very important process in all living organisms and during the division, DNA replication, as well as cell growth also takes place. All these processes, i.e., cell division, DNA replication, and cell growth, have to take place in a coordinated way to ensure correct division and formation of progeny cells containing intact genomes and in the solutions for NCERT class 11 biology chapter 10 cell cycle and cell division you will get all the answers related to this topic only.

The cell cycle is divided into two basic phases:

  • Interphase
  • M Phase (Mitosis phase)

The interphase is divided into three further phases:

  • G 1 phase (Gap 1)
  • S phase (Synthesis)
  • G 2 phase (Gap 2)

After going through CBSE NCERT solutions for class 11 biology chapter 10 cell cycle and cell division, you must be able to understand the answer of the following questions which are given below:

NCERT solutions for class 11 biology chapter 10 cell cycle and cell division- Solved Exercise Questions

Q1. What is the average cell cycle span for a mammalian cell?

Answer:

The average cell cycle span for a mammalian cell is 24 hours.

Q2. Distinguish cytokinesis from karyokinesis.

Answer:

The differences between cytokinesis and karyokinesis are as follows:

Cytokinesis Karyokinesis
The process of division of cytoplasm is called cytokinesis The process of division of the nucleus is called karyokinesis
Cytokinesis takes place after the end of M-phase  Karyokinesis take place during the M-phase

Q3. Describe the events taking place during interphase.

Answer:

Interphase refers to the phase in the cell cycle which prepares the cell and its nucleus for the division. Interphase is divided into three sub-phases like G_{1}, S and G_{2}

1. G1 phase- It is the longest stage of interphase, also called the first growth phase or post-mitotic gap phase. Both the cell and its nucleus grow in size. There is the synthesis of RNA, proteins, nucleotides, amino acids for histones and energy-rich compounds. There is a checkpoint called G1 cyclin or CG1, where the decision about the entry in the G0 stage is taken. If the decision is made cell cycle goes on uninterrupted or the cell undergoes the G0 stage. It refers to the resting phase in which the cell is arrested and not allowed to divide. 

2. S Phase- In this phase, chromosomes along with their DNA replicates. The content of DNA doubles up, however, the number of chromosomes remains the same. After replication, the daughter chromosomes remain attached in the region of the centromere. The centrosome, if present begins to divide. 

3. G2 phase- This phase is characterised by increased synthesis of RNA and proteins. The cell organelles undergo multiplication in this phase while the cell grows in size. G2 phase is also called as second growth phase or pre-mitotic gap phase. 

NCERT solutions for class 11 biology chapter 10 cell cycle and cell division:

Q4. What is Go (quiescent phase) of cell cycle?

Answer:

Go (quiescent phase)- It refers to the stage of inactivation of cell cycle due to the absence of mitogens and energy-rich compounds. The cells of this stage are metabolically active and they act as reserve cells i.e. they undergo growth and differentiation for a specific function. E.g Cells in the quiescent centre of the root tip.

Q5. Why is mitosis called equational division?

Answer:

Mitosis is called equational division because, at the end of mitosis, the numbers of chromosomes remain same in parental cells and daughter cells. Similarly, the ploidy of the parental and daughter cells also remain the same in mitosis.

Q6. Name the stage of cell cycle at which one of the following events occur:

(i) Chromosomes are moved to spindle equator.

Answer:

   (i) Chromosomes are moved to spindle equator

       During metaphase, the chromosomes move to the spindle equator and align themselves there.

Q6. Name the stage of cell cycle at which one of the following events occur:

(ii) Centromere splits and chromatids separate.

Answer:

    (ii) Centromere splits and chromatids separate

        During anaphase, the centromere splits and chromatids are separated. These chromatids after separation move to the opposite poles. 

Q6. Name the stage of cell cycle at which one of the following events occur:

(iii) Pairing between homologous chromosomes takes place.

Answer:

     (iii) Pairing between homologous chromosomes takes place

       The pairing between homologous chromosomes takes place during zygotene of prophase I of meiosis I. As a result of this pairing bivalents are formed.

Q6. Name the stage of cell cycle at which one of the following events occur:

(iv) Crossing over between homologous chromosomes takes place.

Answer:

   (iv) Crossing over between homologous chromosomes takes place

     Crossing over between homologous chromosomes takes place during pachytene of prophase I of meiosis I.

Q7.    Describe the following:

(a) synapsis

Draw a diagram to illustrate your answer.

Answer:

Synapsis- The process of the pairing of homologous chromosomes during the zygotene stage of prophase I of meiosis I is called synapsis. During synapse, a synaptonemal complex is formed by the homologous chromosome which is referred to as a bivalent or a tetrad.

Q7. Describe the following:

(b) bivalent

Draw a diagram to illustrate your answer.

Answer:

Bivalent- it refers to the structure formed by a pair of the synapsed homologous chromosome. 

Chomosome

 

Q7. Describe the following:

(c) chiasmata

Draw a diagram to illustrate your answer.

Answer:

Chiasmata- These are points of attachment between homologous chromosomes during their separation in diplotene to metaphase I stage of meiosis. Chiasmata are initially formed in the regions of crossing over between nonsister chromatids but later on, tend to shift sideways. 

Chiasmata

Q8. How does cytokinesis in plant cells differ from that in animal cells?

Answer:

The process of cytokinesis differs in plant and animal cells

Cytokinesis in plants Cytokinesis in animals

It occurs by cell plate method

It takes place by cleavage method
The spindle persists during cytokinesis Spindle starts to degenerate after anaphase
Cell plate grows centrifugally  Cleavage takes place centripetally
The new cell membrane is derived from vesicles of Golgi apparatus The new cell wall is derived from the endoplasmic reticulum

CBSE NCERT solutions for class 11 biology chapter 10 cell cycle and cell division:

Q9. Find examples where the four daughter cells from meiosis are equal in size and where they are found unequal in size.

Answer:

Meiosis is the reductional division that leads to the formation of four daughter cells which have half the number of chromosomes than the parent cell. Meiosis takes place during spermatogenesis and oogenesis in humans. During spermatogenesis, the daughter cells or sperms formed are equal in size while during oogenesis the daughter cells are unequal in size. 

Q10. Distinguish anaphase of mitosis from anaphase I of meiosis.

Answer:

Anaphase of mitosis Anaphase I of meiosis                 

Anaphase of mitosis involves splitting of each chromosome at centromere into two sister chromatids which start moving towards the opposite poles.

Anaphase of mitosis

Anaphase I of meiosis I involve the separation of homologous chromosomes, while the chromatids remain attached at their chromatids. 

Anaphase I of meiosis   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q11. List the main differences between mitosis and meiosis.

Answer:

Mitosis Meiosis
It takes place in somatic cells It takes place in germ cells
The cells undergoing mitosis can be diploid or haploid The cells that undergo meiosis cannot be haploid
It involves a single division producing two daughter cells at the end It involves two divisions that give rise to four daughter cells
The daughter cells formed after mitosis are exactly similar to their parent cell The daughter cells formed after meiosis are neither similar to the parent one nor to one another
The number of chromosome remains the same after meiosis The number of chromosomes is reduced to half after meiosis. 
Mitosis helps in multiplication of cells, healing and repair Meiosis is involved in the formation of meiospores or gametes

 

Q12. What is the significance of meiosis?

Answer:

The process of meiosis is essential for all sexually reproducing organisms. It occurs in reproductive cells to form gametes that have half the number of chromosomes of the reproductive cells. The two gametes from reproductive cells fuse with each other to form a zygote. As a result, the zygote comes to have a double number of chromosomes. Thus, meiosis maintains the chromosome number of organisms. apart from this, there are other significances of meiosis also. Some of these are as follows

1. Meiosis form gametes that are required for sexual reproduction

2. Meiosis maintains the fixed number of chromosomes in sexually reproducing organisms by having the same during gametogenesis

3. In meiosis, paternal and maternal chromosomes assort independently. It causes a reshuffling of chromosomes and the traits controlled by them. The variations help the breeders in improving the races of useful plants and animals. 

4. Meiosis introduces a new combination of traits or variations. 

5. Chromosomal and genomic mutations occur by irregularities of meiotic division. Some of these mutations are useful to the organism. 

Solutions for NCERT class 11 biology chapter 10 cell cycle and cell division:

Q13.  Discuss with your teacher about

(i) haploid insects and lower plants where cell-division occurs

Answer:

In some lower plants and haploid insects such as drones of a honey bee, meiosis occurs in the zygote. This type of meiosis is called zygotic meiosis whereas this type of life cycle is called haplontic life cycle. 

Q13. Discuss with your teacher about

(ii) some haploid cells in higher plants where cell-division does not occur.

Answer:

Synergids and antipodals are haploid cells in higher plants where cell division does not occur.

Q14. Can there be mitosis without DNA replication in 'S' phase?

Answer:

Without DNA replication in 'S' phase, mitosis cannot occur. During DNA replication, DNA duplicates and this is a very important step. If DNA duplication does not occur than even in mitosis, there will be a reduction in the number of chromosomes of daughter cells. Thus, mitosis cannot occur without DNA replication.

Q15. Can there be DNA replication without cell division?

Answer:

Yes, DNA replication can occur without being followed by cell division. For example, polyteny is a condition in which chromosomes repeatedly replicates but the cells do not divide and as a result of this, DNA accumulates in the cell.

NCERT solutions for class 11 biology chapter 10 cell cycle and cell division:

Q16. Analyse the events during every stage of cell cycle and notice how the following two parameters change

(i) number of chromosomes (N) per cell

Answer:

The number of chromosomes (N) per cell changes during the anaphase I stage of meiosis I. During this stage, the homologous chromosomes get separated and starts moving towards the opposite poles. Thus, the bivalents get divided into sister chromatids. This leads to a reduction of the number of chromosomes to half in daughter cells. 

Q16. Analyse the events during every stage of cell cycle and notice how the following two parameters change

(ii) amount of DNA content (C) per cell

Answer:

The amount of DNA content per cell changes during 'S' phase and anaphase. In 'S' phase, the number of chromosomes remains the same but DNA replicates. Due to DNA replication, the content of DNA doubles up from 1C to 2C or from 2C to 4C depending on whether the cell is diploid or haploid. In anaphase II, the DNA Content decreases to one half from 2C to 1C.

If you have any query in understanding these solutions which are mentioned in the above, then again go through the chapter of the NCERT textbook. And then, try to solve them by yourself and compare them with NCERT solutions for class 11 biology chapter 10 cell cycle and cell division. This will help you not only for your school exam as it will also help you in the preparation of other competitive exams like NEET.

NCERT Solutions for class 11 Biology

Chapter 1

NCERT solutions for class 11 biology chapter 1 the living world

Chapter 2

Solutions of NCERT for class 11 biology chapter 2 biological classification

Chapter 3

CBSE NCERT solutions for class 11 biology chapter 3 plant kingdom

Chapter 4

NCERT solutions for class 11 biology chapter 4 animal kingdom

Chapter 5

Solutions for NCERT class 11 biology chapter 5 morphology of flowering plants

Chapter 6

CBSE NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants

Chapter 7

NCERT solutions for class 11 biology chapter 7 structural organisation in animals

Chapter 8

Solutions for NCERT Class 11 Biology Chapter 8 Cell: The Unit of Life

Chapter 9

CBSE NCERT Solutions for Class 11 Biology Chapter 9 Biomolecules

Chapter 10

NCERT Solutions for Class 11 Biology Chapter 10 Cell Cycle and Cell Division

Chapter 11

Solutions for NCERT Class 11 Biology Chapter 11 Transport in Plants

Chapter 12

CBSE NCERT Solutions for Class 11 Biology Chapter 12 Mineral Nutrition

Chapter 13

NCERT Solutions for Class 11 Biology Chapter 13 Photosynthesis in Higher Plants

Chapter 14

Solutions for NCERT Class 11 Biology Chapter 14 Respiration in Plants

Chapter 15

CBSE NCERT Solutions for Class 11 Biology Chapter 15 Plant Growth and Development

Chapter 16

NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption

Chapter 17

Solutions for NCERT Class 11 Biology Chapter 17 Breathing and Exchange of Gases

Chapter 18

CBSE NCERT Solutions for Class 11 Biology Chapter 18 Body Fluids and Circulation

Chapter 19

NCERT solutions for class 11 biology chapter 19 excretory products and their elimination

Chapter 20

Solutions for NCERT class 11 biology chapter 20 locomotion and movement

Chapter 21

CBSE NCERT solutions for class 11 biology chapter 21 neural control and coordination

Chapter 22

NCERT solutions for class 11 biology chapter 22 chemical coordination and integration

NCERT Solutions for Class 11- Subject wise

NCERT solutions for Class 11 Maths

Solutions for NCERT Class 11 Chemistry

CBSE NCERT solutions for Class 11 Physics

What are the benefits of NCERT solutions for class 11 biology chapter 10 cell cycle and cell division:

  • NCERT is the base of your learning.
  • You will get all the answers to this chapter and it will help you to score good marks in the exam.
  • CBSE NCERT solutions for class 11 biology chapter 10 cell cycle and cell division will also help you with competitive exams like NEET.
  • Solutions for NCERT class 11 biology chapter 10 cell cycle and cell division will also help you in your 12th board exam.
  • It will also boost your knowledge.
 

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