WBBSE Solutions For Class 10 Life Science And Environment Chapter 2 Mitotic And Meiotic Cell Division

Chapter 2 Mitotic And Meiotic Cell Division Summary

WBBSE Class 10 Mitosis Overview

• Mitotic cell division is mainly divided into two parts karyokinesis and cytokinesis. In karyokinesis, the division of the nucleus occurs in four stages-prophase, metaphase, anaphase and telophase and after completing karyokinesis, cytokinesis or cytoplasmic division takes place.
• As said earlier, karyokinesis occurs in four phases-prophase, metaphase, anaphase and telophase. In prophase, chromatins are getting packed densely to form chromosomes along with spindle fibre.
• In metaphase, chromosomes become arranged in an equatorial line. Chromatids move to opposite poles, during anaphase. And lastly, during telophase two daughter nuclei are formed at two poles of the cell.
• The cytokinesis process is quite different in animal and plant cells. In the case of animals, the cleavage method takes place to complete this process but in case of plant cells, cell plate formation is mandatory for cytokinesis.
• Along with mitosis, meiosis cell division also takes place. It is important for the formation of the gamete. Meiosis is of two types-Meiosis I also known as reductional division and meiosis II, which is also known as equational division.
• Like mitosis, meiosis is also divided into karyokinesis through prophase, metaphase, anaphase and telophase and cytokinesis. Though in the mitotic division, the number of chromosomes stays constant, in the meiotic division the chromosome number reduces to half.
• During gametogenesis by meiosis, crossing occurs between two non-sister chromatids of two homologous chromosomes, helping to produce a variation.

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Chapter 2 Mitotic And Meiotic Cell Division Long Answer Type Questions

Question 1. Mention the different phases of mitosis and point out the main events of each phase.

Answer:

Different phases of mitosis and the main events of each phase:

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Mitosis occurs in two main phases, karyokinesis or nuclear division and cytokinesis or cytoplasmic division. Karyokinesis is subdivided into four phases-prophase, metaphase, anaphase and telophase. The main events of these phases are mentioned below.

Question 2. Describe the prophase of mitosis in plant and animal cells.

Answer:

Prophase of mitosis in plant and animal cells:

The first phase of karyokinesis is called prophase. The events which take place during this phase, in both plant and animal cells, are discussed here.

Prophase in plant cells:

The events occurring during prophase in plant cells are as follows-

1. During this phase, the nucleus swells.
2. The chromatin reticular start coiling, get dehydrated and form chromosomes.
3. Each chromosome appears with two chromatids, which remain attached to each other by the centromere.
4. Chromatids undergo coiling or serialisation to make the chromosome thick.
5. Nucleolus gradually diminishes in size. At the end of this phase, both the nucleolus and nuclear membrane disappear.
6. Within the cytoplasm, microtubules grow, which form the ancestral spindle during the later phases.

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2. Prophase in animal cells:

The above-mentioned events also occur in animal cells except for the development of microtubules for spindle formation. Other than these, certain typical events occur in animal cells during prophase.

These are as follows-

1. The two centrosomes with paired centrioles, formed during interphase, start moving to two opposite poles of the cell during early prophase.
2. Astral rays radiate from the two centrosomes. Gradually, the rays grow in length, which in the later phase, prepare the astral spindle.

Stages of Mitosis Explained

Question 3. Describe the metaphase of mitosis in plant and animal cells.

Answer:

Metaphase of mitosis in plant and animal cells:

The second phase of karyokinesis is called metaphase. The events occurring during this phase in both plant and animal cells are discussed below.

1. Metaphase in plant cells:

The events occurring during metaphase in plant cells are as follows-

1. The nuclear membrane and nucleolus disappear completely.
2. Cytoplasmic microtubules arrange to form a spindle. This spindle is formed without the involvement of the centrosome, therefore, it is called an astral spindle.This spindle comprises two types of fibres, which are-
3. Chromosomal spindle fibres, which bind one pole of the spindle to the centromere of chromosomes and
4. Continuous spindle fibres, which connect the two poles of the spindle.
5. All the chromosomes arrange along the equatorial plane of the dividing cell and the chromatids of each chromosome stay parallel to that plane. This typical distribution of the chromosomes forms the metaphase plate or equatorial plate across the cell.
6. Chromosomes become the densest and thickest.
7. At the end of this phase, the centromere of each chromosome starts to split longitudinally.

2. Metaphase in animal cells:

All the above-mentioned events occur in animal cells also, except the spindle formation. Here, the spindle is formed by the extension of astral rays from the centrioles, positioned at the two opposite poles of the dividing cell.

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Question 4. Describe the anaphase of mitosis in plant and animal cells. Or, Mention three changes that occur in the anaphase stage of mitosis in animal cells.
Or,
Draw a neat diagram of the anaphase of mitosis of an animal cell and label the following parts:

1. Polar region,
2. Spindle fibre,
3. Chromatid,
4. Centromere.

Answer:

Anaphase of mitosis in plant and animal cells:

The third phase of karyokinesis, in which the daughter chromosomes move from the equatorial plate towards the two opposite poles of the dividing cell, is called anaphase. The events which occur during this phase, in both plant and animal cells, are discussed below.

1. Anaphase in plant cells:

The events occurring during anaphase, in plant cells, are as follows-

1. The Centromere of each chromosome splits longitudinally, as a result, two sister chromatids separate from each other with their own share of centromere and emerge as two daughter chromosomes.
2. The Centromere of each daughter chromosome remains attached to the chromosomal spindle fibre.
3. Inter-polar or Chromosomal continuous spindle fibres connect the two poles of the -spindle fibre spindle.
4. Gradually, the chromosomal fibres contract. -Chromatid to pull half of the daughter chromosomes towards one separation Inter-zonal pole and the remaining half to the opposite pole. This is a spindle fibre called anaphasic movement.
5. During anaphasic, movement, metacentric, sub-metacentric, acrocentric and telocentric chromosomes appear like the English letters ‘V’ ‘L’, ‘J’ and ‘I’ respectively, based on the position of centromere on the chromosome.

2. Anaphase in animal cells:

The above-mentioned events also occur during anaphase in animal cells. Here, inter-zonal spindle fibres cluster in between separating chromosomes to form columnar stem bodies, which help in anaphasic movement.

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Question 5. Describe the telophase of mitosis in plant and animal cells.

Answer:

Telophase of mitosis in plant and animal cells:

The fourth phase of karyokinesis, in which two daughter nuclei are formed within a dividing cell, is called telophase. The events which take place during this phase, in both plant and animal cells, are discussed below.

Telophase in plant cells:

The events occurring during telophase, in plant cells, are as follows-

1. At the start of telophase, an equal number of chromosomes reach the two opposite poles of the spindle.
2. The chromosomes uncoil and rehydrate to become thin and long to form chromatin.
3. The nuclear membrane reappears around chromatin.
4. Nucleolus reappears within the nucleus.
5. Finally, two equal numbers of chromosome-bearing and morphologically identical nuclei form within the dividing cell.
6. After the formation of two daughter nuclei, during the end of telophase, cell plate formation starts by deposition of phragmoplast granules in the equatorial plane of the cell.

2. Telophase in animal cells:

The events of telophase in animal cells are the same as that of plant cells except, in the case of animal cells a cleavage or furrow appears in between the cytoplasm during the late telophase stage, instead of phragmoplast.

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Meiosis vs Mitosis Comparison

Question 6. Describe the events occurring during cytokinesis in plant and animal cells.

Answer:

Cytokinesis in plant and animal cells:

The cytokinesis phase actually starts from the late telophase stage and continues until the cytoplasm of the cell divides into two halves, thus creating two daughter cells.

1. Cytokinesis in plant cells:

The events which occur during cytokinesis in plant cells are as follows-

1. At the end of telophase, microtubules, microfilaments and endoplasmic reticular elements arrange along the equatorial plane to form phragmoplast.
2. Golgi vesicles align along the two sides of the phragmoplast and form the cell membrane of the two daughter cells.
3. In the course of time, the phragmoplast forms a thin cell plate, which transforms into middle lamella, composed of calcium and magnesium pectate.
4. Cellulose, hemicellulose, callose etc. accumulate at two sides of the middle lamella to form the primary cell wall. With the formation of the primary cell wall, the cytoplasm of the mother cell separates completely to give rise to two daughter cells.

2. Cytokinesis in animal cells:

The events which occur during cytokinesis in animal cells are as follows-

1. At the start of telophase, the cell membrane moves inward along the equatorial line to form a constriction or furrow. Microfilaments accumulate below the cell membrane and their interaction pulls it to develop the furrow.
2. With time, as the cell enters cytokinesis, the furrow grows deeper and finally separates the cytoplasm to form two identical daughter cells.

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Cytokinesis in animal cells is therefore known as furrowing or cleavage.

Question 7. Distinguish between mitosis in plant and animal cells based on spindle formation and cytokinesis. What is mitotic meiosis?

Answer:

Differences between mitosis in plant cells and animal cells:

Mitotic meiosis

The haploid daughter cells produced during meiosis-I, undergo equational division in meiosis-II. Therefore, meiosis II is known as mitotic meiosis.

Question 8. Briefly describe the main features of meiosis-I and meiosis-II.

Answer:

Main features of meiosis-l:

The main features of meiosis-I are given below.

1. Chromosomal separation:

1. During prophase-I of meiosis-I, an exchange of chromosomal materials occurs between homologous chromosomes.
2. In metaphase-I, the homologous chromosome pairs arrange along the equatorial plane.
3. In anaphase-I, homologous chromosome pairs separate and two separated sets of chromosomes move towards two opposite poles of the cell.

2. Reduction in chromosome number:

In meiosis-I, each daughter nucleus gets half the pairs of homologous chromosomes. Therefore, the chromosome number of the daughter cell reduces to half of the somatic cell.

3. Crossing over:

The exchange of portions between non-sister chromatids of homologous chromosomes occurs in meiosis-1. This is called crossing over. In this process, the chromosomes get new genetic combinations.

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Main features of meiosis-II:

The main features of meiosis-II are given below.

1. Separation of chromosomes:

In anaphase of meiosis-II, the centromere of each chromosome splits, and sister chromatids get their share of centromeres and are transformed into daughter chromosomes.

Two sets of daughter chromosomes move to two opposite poles of the cell and get into two daughter nuclei.

2. Equational division:

Unlike mitosis, meiosis-II involves a haploid set of chromosomes. However, equal division of chromosomes takes place in meiosis II. As a result, the chromosome number of the daughter cells of meiosis-I and daughter cells of meiosis-II remains identical.

Question 9. Why is meiosis called reduction division? Distinguish between mitosis and meiosis based on site of occurrence, nature of chromosomal division and number of cells produced.
Or,
Meiosis is characteristically different from mitosis-how would you justify the statement?

Answer:

Meiosis is called as reduction division:

In meiosis, the chromosome number of a diploid mother cell reduces to its half to give rise to a haploid number of chromosome-bearing daughter cells. Thus, meiosis is called reduction division.

Differences between mitosis and meiosis:

Phases of Meiosis

Question 10. Explain the process of crossing over and reduction in chromosome number. Mention the significance of crossing over and reduction in chromosome number in meiosis.

Answer:

Process of crossing over and reduction in chromosome number:

The reduction of chromosome number through the process of crossing over are given here.

1. Crossing over:

During prophase, homologous chromosomes arrange in parallel pairs, this event is called synapsis. The paired homologous chromosomes are known as bivalent. Later, each chromosome splits longitudinally into two sister chromatids.

In this state, the bivalent appears with four chromatids, which is called a tetrad. While coiling, the non-sister chromatids of a tetrad cross over each other at some points, which appear as chi. These points are called chiasmata.

During crossing over, non-sister chromatids reciprocally exchange their segments, which results into new allelic combinations in the homologous chromosomes.

2. Reduction in chromosome number:

In anaphase-1, homologous chromosome pairs separate and the two separated sets of chromosomes move towards two opposite poles of the cell. Finally, during telophase-1, each set of chromosomes gets into each of the daughter nuclei.

By this process, a diploid number of chromosomes of the mother cell becomes haploid in daughter cells.

Significance of crossing over and reduction in chromosome number in meiosis:

The significance of crossing over and reduction in chromosome number in meiosis are given below.

1. Significance of crossing over:

By means of crossing over, genetic recombination takes place, which creates variation. Crossing over confirms the linear arrangement of genes on a chromosome.

2. Significance of reduction in chromosome number:

In meiosis, chromosome number reduces to give rise to haploid gametes. After fertilisation of two haploid gametes, diploid zygotes are formed. By this process, the chromosome number of a species remains constant.

Question 11. Write down the significance of mitotic cell division.

Answer:

Significance of mitotic cell division:

The significance of miotic cell division in plant and animal cells is mentioned below.

1. Growth in size:

The number of somatic cells in any organism increases by continuous mitotic division. Through this process, the overall size of the organism increases. The unicellular zygote undergoes mitosis to develop into a multicellular organism.

2. Cell replacement and healing of wounds:

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The damaged and aged cells of the body are replaced by new cells through mitotic division of the healthy neighbouring cells. This process heals any wound of our body.

For example, the epidermal cells of our body are depleted continuously by friction. These are replenished very quickly by the process of mitosis.

3. Regeneration:

Certain animals have the ability to regenerate their lost body parts. Arms of starfish, appendages of prawns and crabs, tail of house-lizard etc. can be regenerated. Mitotic cell division makes it possible.

4. Reproduction:

Several unicellular organisms undergo mitosis to perform asexual reproduction. Amoeba, Paramoecium, yeast etc. perform asexual reproduction by mitosis. The vegetative reproduction in plants like water hyacinth, sweet potato, Bryophyllum etc. occurs by mitosis.

5. Equational division:

The daughter cells produced by mitosis are genetically and morphologically identical to their mother cell. This process is essential to maintain the integrity of the cellular character of a tissue.

Question 12. What is meiosis? Explain the significance of meiosis.

Answer:

Meiosis:

The cell division in which, a germ mother cell of a diploid organism or zygote of a haploid organism undergoes two successive divisions to give rise to four daughter cells, each carrying half the number of chromosomes of its mother cell, is called meiosis.

Significance of meiosis:

The significance of meiosis are given below.

1. Keeping the chromosome number of a species constant:

During meiosis, chromosome number in daughter cells reduces to half of that of their mother cell. The haploid gametes, produced by this process, undergo fertilisation to produce a diploid zygote, which finally develops into a full-grown organism.

By this process, the chromosome number of parents remains identical to that of their offspring. If there had been no meiosis, the number of chromosomes in sexually reproducing organisms would have increased geometrically with generations.

2. Origin of genetic variation:

During crossing over, the exchange of segments of chromatids takes place between homologous chromosomes. By this process, the recombination of genes occurs, which results in the origin of new genetic variations.

3. Gamete formation:

By meiosis, haploid gametes (sperms and eggs) are formed from diploid germ mother cells.

4. Maintenance of alternation of generation:

By this cell division, a cyclic alternation occurs between diploid sporophytic generation and haploid gametophytic generation in several organisms. Thus, alternation of generation is maintained.

Question 13. Distinguish between-

1. Mitosis and amitosis,
2. Karyokinesis and cytokinesis.

Answer:

Differences between mitosis and amitosis

Differences between karyokinesis and cytokinesis

Question 14. Distinguish between

1. Meiosis-I And meiosis-II,
2. Cytokinesis in plant cells And animal cells.

Answer:

Differences between meiosis-I and meiosis-II

Differences between cytokinesis in plant cells and animal cells

Question 15. Draw a neat diagram of the metaphase of mitosis of a plant c cell or an animal cell division and label the following parts:

1. Chromosome,
2. Spindle fibre,
3. Polar region,
4. Centromere

Similar Question, Draw a neat diagram of the metaphase of mitotic cell division in an animal  cell and label the following parts:

1. Chromatid,
2. Centromere,
3. Polar region,
4. Spindle fibre.

Answer:

Chapter 2 Mitotic And Meiotic Cell Division Short Answer Type Questions

Question 1. In which phase of mitosis the chromosomes appear with two chromatids (become double-stranded) and in which phase they appear again as single-stranded chromosomes?

Answer:

In late prophase, the chromosomes appear double-stranded with two chromatids. In anaphase, the chromatids reappear as single-stranded chromosomes.

Question 2. What are stem bodies?

Answer:

Stem bodies:

During anaphase in animal cells, several inter-zonal fibres appear as column-like structures in between the spindles. These structures are called stem bodies.

Question 3. What will happen to a cell if karyokinesis continues in it, but cytokinesis does not?

Answer:

If karyokinesis continues in a cell without cytokinesis, the cell will become multi-nucleated but the number of cells will not increase. Such cells with multiple nuclei in plants are known as coenocytes and in animals, it is known as syncytium.

Question 4. What are spindle fibres? Mention their types.

Answer:

Spindle fibres:

Spindle fibres are fine microtubular filaments, which are arranged like a spindle within a dividing cell. Spindle fibres hold the chromosomes at the equatorial plane and then shrink to help in the anaphasic movement of the chromosomes.

Types of spindle fibres:

Spindle fibres are of three types-chromosomal fibres, interpolar fibres or continuous fibres and inter-zonal fibres.

Question 5. At which position of a cell do the chromo- somes are arranged during metaphase? How many types of chromatin are seen in a nucleus?

Answer:

Arrangement of chromosomes during metaphase:

During metaphase, the chromosomes are arranged along the equatorial plane of the dividing cell.

Types of chromatin in a nucleus:

There are two types of chromatin found in a nucleus. These are euchromatin and heterochromatin.

Question 6. What is meant by bivalent and tetrad?

Answer:

Bivalent:

During the zygotene sub-phase of pro-phase-I in meiosis-1, homologous chromosomes come side by side to form pairs. These pairs of homologous chromosomes are called bivalent.

Tetrad:

During the pachytene sub-phase of prophase- I in meiosis-I, each chromosome of a bivalent splits along the length into two chromatids. At this state, each bivalent appears four-stranded, which is called a tetrad.

Question 7. How can you distinguish between the mitosis of plant cells and that of animal cells on the basis of the formation of spindle fibre and the process of cytokinesis?

Answer:

Distinguish between the mitosis of plant cells and that of animal cells are-

Question 8. What are chiasmata?

Answer:

Chiasmata:

During the late pachytene sub-phase of prophase I in meiosis-I, the non-sister chromatids of a tetrad cross over each other at certain points. These crossing points appear as the Greek letter chi (x).

These points of crossing over are called chiasmata (singular-chiasma).

Importance of Cell Division in Growth

Question 9. What is interkinesis?

Answer:

Interkinesis:

The brief phase in between meiosis-I and meiosis II is known as interkinesis. During this phase, DNA synthesis does not occur like interphase.

Question 10. What are meant by a sister and non-sister chromatids?

Answer:

A sister and non-sister chromatids:

In the zygotene sub-phase of meiotic prophase-I, the homologous chromosomes undergo pairing to form bivalent. During pachytene, each of the homologous chromosomes splits into two chromatids to form a four-stranded tetrad.

Out of these, the two chromatids of the same chromosome are called sister chromatids, whereas the two chromatids of two different chromosomes of a homologous pair are called non-sister chromatids.

Question 11. Mention the main features of meiosis-l.

Answer:

The main features of meiosis-I are as follows-

1. In meiosis-I, crossing over and recombination of genes occur between homologous chromo- somes.
2. The homologous pairs separate and each chromosome of the pairs move towards the two opposite poles of the cell.
3. Finally, two hap-loid daughter nuclei are formed from a diploid (2n) nucleus.

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Question 12. Mention the main features of meiosis-II.

Answer:

The main features of meiosis-II

Events of meiosis-II are identical to a mitotic division. In anaphase of meiosis-II, chromatids of a chromosome split to form two separate chromosomes. Two haploid cells, produced after meiosis-I, divide in this phase to give rise to four haploid daughter cells.

Question 13. Mention two points of significance of meiotic cell division.

Answer:

Two points of significance of meiotic cell division are as follows-

1. By meiotic cell division, chromosome number of sexually reproducing organisms reduces to half, so that it remains constant after fertilisation.
2. In meiosis, the recombination of genes takes place, which produces new genetic variations and helps the organisms in adaptation and evolution.

Question 14. A somatic cell of a plant has 18 chromosomes. What will be the number of chromosomes in its

1. Root cells,
2. Endosperm nucleus and
3. Definitive nucleus?

Answer:

A somatic cell is diploid, hence, 2n=18. Therefore

1. The chromosome number of the root cells will be 2n=18,
2. The chromosome number of the endosperm nucleus will be 3n=27,
3. The chromosome number of the definitive nucleus will be 2n=18.

Question 15. What do you know about synapsis and syndesis? What is the significance of synapsis?

Answer:

Syndesis:

The pairing of two homologous chromosomes, at prophase I of meiosis I is called synapsis or syndesis. The synaptonemal complex helps in a pairing of this chromosome.

Significance:

By the process of synapsis, chiasma formation and crossing over take place. This leads to variation in new progeny.

Question 16. What do you know about dyad and monads?

Answer:

Dyad:

After completing the replication of the DNA of a chromosome, a conjugated pair of homologous chromosomes or sister chromatids are formed, called a dyad. This type of structure is mainly seen in prophase and metaphase.

Monad:

The single chromatid of chromosomes is called a monad. This type of structure is mainly seen in anaphase.

Question 17. What do you know about disjunction? When it is seen?

Answer:

Disjunction:

During anaphase of cell division, two chromatids of each chromosome moves to the opposite direction due to the constriction of the spindle fibre. This ‘process is called a disjunction. It is seen at the begin- ing of the anaphase stage of mitosis and meiosis.

Question 18. What is meant by crossing over?

Answer:

Crossing over:

In the pachytene sub-phase of meiotic prophase-I, the non-sister chromatids of homologous chromosome pairs cross each other at a number of points.

At these points of crossing, the chromatids cut and exchange the segments with each other. As a result, the chromosomes get new genetic combinations and this event is known as crossing over.

Question 19. What is the significance of crossing over?

Answer:

The significance of crossing over:

Body part exchange between two homologous chromosomes takes place during crossing over. This generates variation in the gamete. This variation brings new characters which helps in adaptation.

Question 20. What is the spindle apparatus?

Answer:

The spindle apparatus:

The specialized structure composed of centriole and spindle fibre to which chromosomes are attached during cell division is called the spindle apparatus.

Question 21. What is phagosome? What is its significance?

Answer:

1. Pharagmosome: The thin cytoplasmic plate that form at the middle of the cell during miotic division in a plant cell is called phagosome.
2. Significance: It helps in phragmoplast formation.

Question 22. What Is a metaphase plate?

Answer:

Metaphase plate:

All the chromosomes are arranged in the equatorial line of the cell during mitosis and meiotic cell division. This looks like a plate-like structure called metaphase plate.

Question 23. What is the synaptonemal complex?

Answer:

The synaptonemal complex:

The synaptonemal complex is a proteinaceous between two fibrous structures formed by homologous chromosomes during prophase I. It helps two forms divalent.

Question 24. What will happen if cytokinesis does not take place?

Answer:

If cytokinesis does not take place then the two cells will not separate. As a result a binucleate cell. will be formed. For example, an osteoclast cell of bone is such a cell with many nuclei.

Question 25. “In case of prophase and telophase changes of opposite nature happens”-Write two such changes.

Answer:

“In case of prophase and telophase changes of opposite nature happens”

In prophase, the nucleus and nucleolus get disappeared, but it reappeared in telophase.

In prophase, chromatin fibre gets condensed to form a distinct chromosome. Whereas in the case of telophase, the chromosome begins to uncoil and hydrated to form fine chromatin reticular.

Question 26. During the meiosis cell division, a reduction in the number of chromosomes and exchange of segments between chromatids take place- Analyze what are the significances of these two phenomena.

Answer:

During meiotic division, the number of chromosomes get reduced from 2n to n for gamete formation. Because during fertilization two cells get fused with each other and form Zygote (2n).

So if these cells have contain 2n chromosomes then the zygote will possess 4n number of chromosome, that is not impossible for the existence of an organism. For that reason, the gamete should contain only half the number of chromosomes (n).

This reduction in chromosome number is only possible because of meiotic division. Another important phenomenon is an exchange of segments between two chromatids.

This exchange can play an important role in genetic recombination, that will give rise to variation in the new progeny. This variation is most important for the newly formed progeny because it helps them tp with the changed environment and to survive. this has an ultimate effect on evolution.

Question 27. Differentiate between synapse and synapsis.

Answer:

Differences between synapse and synapsis are-

Question 28. Differentiate between Meiosis I and Meiosis II.

Answer:

Differences between meiosis I and meiosis II are-

Question 29. Identify the stages of karyokinesis of mitotic cell division depending on the following features:

1. Alignment of chromosomes along the equator of the cell and their arrangement in a definite pattern.
2. The disintegration of spindle fibre.
3. The disappearance of nuclear membrane and nucleolus.
4. Movement of daughter chromosomes to the opposite poles of the cell.

Answer:

1. Alignment of chromosomes along the equator of the cell and their arrangement in a definite pattern-Metaphase
2. The disintegration of spindle fibre-Telophase
3. The disappearance of nuclear membrane and nucleolus-Prophase
4. Movement of daughter chromosomes to the opposite poles of cell-Anaphase

Chapter 2 Mitotic And Meiotic Cell Division Very Short Answer Type Questions Multiple Choice Questions And Answers [Mcq]

Question 1. Mitotic cell division occurs in—

1. Germ mother cell
2. Egg cell
3. Somatic cell
4. Male gamete

Answer: 3. Somatic cell

Question 2. The phrase, of mitosis in which nucleolus reappears, is—

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Answer: 4. Telophase

Question 3. The Nucleolus of a dividing cell disappears in—

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Answer: 1. Prophase

Question 4. The stage of cell division in which sister chromatids separate and move towards two opposite poles is—

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Answer: 3. Anaphase

Question 5. The term ‘karyokinesis’ was coined by—

1. Lamarck
2. Schleicher
3. Darwin
4. Johannsen

Answer: 2. Schleicher

Question 6. Who first stated that ‘two sets of ceil division occur during the formation of germ cells’?

1. Oparin
2. Haldane
3. Flemming
4. Weismann

Answer: 4. Weismann

Question 7. The formation of cell plate occurs with the help of—

1. Golgi bodies
2. Ribosomes
3. Mitochondria
4. Lysosomes

Answer: 1. Golgi bodies

Question 8. Which of the following help(s) in chromosomal movement during cell division?

1. Spindle fibres
2. Cytoplasm
3. Ribosomes
4. Mitochondria

Answer: 1. Spindle fibres

Question 9. Which of the following phases of cell division is a complex process?

1. Amitosis
2. Meiosis-I
3. Meiosis-II
4. Mitosis

Answer: 2. Meiosis-I

Question 10. Determine from the answers given below in which phases of karyokinesis during mitotic cell division following two incidents happen—

1. Daughter chromosomes tend to move apart from each other towards their own poles

2. Nuclear membrane and nucleolus disappear

1. 1 Prophase 2 Anaphase
2. 1 Anaphase 2 Prophase
3. 1 Telophase 2 Metaphase
4. 1 Metaphase 2 Telophase

Answer: 2. 1 Anaphase 2 Prophase

Question 11. The shortest phase of cell division is—

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Answer: 3. Anaphase

Question 12. The longest phase of mitosis is—

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Answer: 1. Prophase

Question 13. In which of the following organisms is an astral mitosis seen?

1. All living beings
2. Higher plants
3. Higher animals
4. Lower animals

Answer: 2. Higher plants

Question 14. Neither chromosomal movement nor disappearance of the nuclear membrane occurs in—

1. Mitosis
2. Meiosis
3. Amitosis
4. Both 1 and 2

Answer: 3. Amitosis

Question 15. During anaphasic movement, metacentric chromosomes appear like—

1. I
2. J
3. V
4. L

Answer: 3. V

Question l6. Sperms and Ova are produced by—

1. Mitosis
2. Meiosis
3. Amitosis
4. Budding

Answer: 2. Meiosis

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Question 17. The mitotic cell division, in which spindle fibres do not grow from the centriole, is called—

1. Equal division
2. Unequal division
3. Astral mitosis
4. Anastral mitosis

Answer: 4. Anastral mitosis

Question 18. The stage, in which you can get the best view of chromosomes within a cell, is—

1. Prophase
2. Anaphase
3. Telophase
4. Metaphase

Answer: 4. Metaphase

Question 19. Which of the following is the unit of crossing over?

1. Chloroplast
2. Ribosome
3. Chromatid
4. Lysosome

Answer: 3. Chromatid

Question 20. If chromosome number of a somatic cell is 46, by which type of cell division will it come down to 23?

1. Mitosis
2. Meiosis
3. Amitosis
4. Budding

Answer: 2. Meiosis

Question 21. The fourth phase of mitosis is called—

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Answer: 4. Telophase

Question 22. Crossing over occurs during—

1. Amitosis
2. Mitosis
3. Meiosis-I
4. Meiosis-II

Answer: 3. Meiosis-I

Wbbse Class X Life Science

Question 23. The stage of cell division, in which astral and ancestral spindles develop respectively in animal and plant cells, is—

1. Early prophase
2. Late prophase
3. Metaphase
4. Anaphase

Answer: 2. Late prophase

Question 24. The main component of the cell wall of a plant cell is called—

1. Chitin
2. Protein
3. Lipid
4. Cellulose

Answer: 4. Cellulose

Question 25. The cell division, in which genetic variation takes place, is—

1. Amitosis
2. Mitosis
3. Meiosis
4. Both 2 and 3

Answer: 3. Meiosis

Question 26. The cell division, in which recombination of genes occurs, is—

1. Meiosis
2. Mitosis
3. Amitosis
4. Both 1 and 2

Answer: 1. Meiosis

Question 27. The chromosome number of germ cells is—

1. Diploid
2. Triploid
3. Polyploid
4. Haploid

Answer: 4. Haploid

Question 28. Spindle fibres are composed of—

1. Humulin
2. Intermediate filament
3. Flagellin
4. Tubulin

Answer: 4. Tubulin

Wbbse Class 10 Life Science Solutions

Question 29. The term ‘cytokinesis’ was coined by—

1. Boveri
2. Remak
3. Whitman
4. LamarckAnswer: 3. Whitman

Question 30. The process of cell division that occurs in germ mother cells to give rise to germ cells is known as—

1. Mitosis
2. Meiosis
3. Amitosis
4. Endomitosis

Answer: 2. Meiosis

Question 31. Cytokinesis in animal cell occurs by—

1. Cell membrane formation
2. Cell plate formation
3. Cleavage or furrowing
4. Anaphasic movement

Answer: 3. Cleavage or furrowing

Question 32. The cell division, in which spindle fibres are not formed, is called—

1. Amitosis
2. Mitosis
3. Meiosis-I
4. Meiosis-II

Answer: 1. Amitosis

Question 33. The cell division that keeps a constant chromosome number of a species, is called

1. Amitosis
2. Mitosis
3. Meiosis
4. Both 1 and 3

Answer: 3. Meiosis

Wbbse Class 10 Life Science Solutions

Question 34. The phase of cell division, in which chromosomes take various shapes based on the location of centromere—

1. Prophase
2. Metaphase
3. Telophase
4. Anaphase

Answer: 4. Anaphase

Question 35. You have to observed the separation of two sister chromatids at one stage of mitotic cell division. The stage is—

1. Prophase
2. Telophase
3. Anaphase
4. Metaphase

Answer: 3. Anaphase

Question 36. In which stage of mitosis cell division, the nuclear membrane and nucleolus are seen to disappear?

1. Anaphase
2. Prophase
3. Metaphase
4. Telophase

Answer: 2. Prophase

1. Question 37. Determine which of the following statement is correct regarding the significance of meiosis—It results in overall growth and development of the body.
2. It results in the growth of reproductive organs and embryo of the organism
3. It produces haploid gamete containing hereditary variations
4. It regenerates the organ in the body of some animals, if it is lost

Answer: 3. It produces haploid gamete containing hereditary variations

 

Chapter 2 Mitotic And Meiotic Cell Division Answer In A Single Word Or Sentence

Question 1. By which type of cell division does a cell develop its own replica?
Answer: By mitotic cell division a cell develops it own replica.

Question 2. Where does mitotic cell division occur?
Answer: Somatic cells of a living organism

Question 3. Which type of cell division increases the number of somatic cells in a living body?
Answer: Mitotic cell division

Question 4. Where does equational cell division occur?
Answer: Somatic cells

Wbbse Class 10 Life Science Solutions

Question 5. Which cellular component is formed to help cytokinesis in a plant cell?
Answer: Formation of cell plate

Wbbse Class X Life Science

Question 6. Where do the chromosomes lie within a cell during metaphase stage of cell division?
Answer: Equatorial plane of a dividing cell

Question 7. How many daughter cells are produced from a single cell after a mitotic division?
Answer: Two daughter cells are produced

Question 8. What is the role of the centrosome in animal cell division?
Answer: Centrosome helps in the formation of spindle fibres.

Question 9. Which parts of a plant cell help in spindle fibre formation during cell division?
Answer: Microtubules of the cytoplasm of a plant cell help in spindle fibre formation during cell division.

Question 10. How will the absence of a centrosome in an animal cell affect cell division?
Answer: The absence of a centrosome in an animal cell will not allow spindle fibre formation and thereby, the cell division process will stop.

Question 11. How many daughter cells will be produced after a single meiosis of a mother cell?
Answer: Four daughter cells will be produced after a single meiosis of a mother cell.

Question 12. Where does meiotic cell division occur?
Answer: Meiotic cell division occurs in the germ mother cell (inside the testis and ovary in animals and anther and ovary of flowers).

Question 13. Where does meiosis occur in lower plants?
Answer: In lower plants, meiosis occurs in zygotes and spore mother cells.

Cell Cycle Phases for Class 10

Question 14. To which portion of a eukaryotic chromosome does spindle fibre attach during metaphase?
Answer: During metaphase, spindle fibres attach to the centromere or kinetochore of an eukaryotic chromosome.

Question 15. What is a dyad?
Answer:

Dyad

A chromosome, with two distinctly visible. chromatids, is called dyads.

Question 16. Which cell organelle takes part in the formation of the two poles of mitotic spindle in an animal cell?
Answer: Centrosome

Wbbse Class X Life Science

Question 17. In which type of cell division does crossing over take place?
Answer: Crossing over takes place in meiotic cell division.

Question 18. Which special cellular components help in cytokinesis in plant cells?
Answer: Phragmoplasts

Question 19. Which type of cell division helps in the healing of wounds in living organisms?
Answer: Mitotic cell division

Question 20. What is Karyokinesis?
Answer:

Karyokinesis

Karyokinesis is the division of the nucleus

Question 21. In which phase of cell division spindle fibre is formed?
Answer: Prophase

Question 22. In which phase of cell division non-disjunction of chromosome takes place?
Answer: Anaphase

Question 23. What is the alternative name of synapsis?
Answer:

Alternative name of synapsis is

Syndesis

Question 24. In which phase of cell division chiasma is formed?
Answer: Prophase I of meiosis

Wbbse Class 10 Life Science Solutions

Question 25. Which protein form the spindle fibre?
Answer: Tubulin

Question 26. Name the five subphases of meiotic prophase I.
Answer:

The five subphases of meiotic prophase I

Leptone, zygotene, pachytene, diplotene and diakinesis.

Common Mistakes in Understanding Cell Division

Question 27. Mention the significance of crossing over.
Answer:

Significance of crossing over

Genetic recombination.

Question 28. Name the phase, where disintegration of spindle fibre occurs.
Answer: Telophase.

Question 29. Name the process by which cytokinesis of the plant cell happen.
Answer: Cell plate formation.

 

Chapter 2 Mitotic And Meiotic Cell Division Fill In The Blanks

Question 1. _________ takes part in spindle formation during animal cell division.
Answer: Centrosome

Question 2. _________ haploid daughter cells are produced by the meiotic division of a single mother cell.
Answer: Four

Question 3. Chromosomal movement is seen during _________ stage.
Answer: Anaphase

Question 4. By the formation of _________, cytokinesis occurs in plant cells.
Answer: Cell plate

Question 5. The intermediate stage in between meiosis-I and meiosis II is_________.
Answer: Interkinesis

Question 6. Each of the homologous pair of chromosomes, which occur during prophase-I is called _________.
Answer: Bivalent

Wbbse Class 10 Life Science Solutions

Question 7. The process of pairing of homologous chromosome pairs is called _________.
Answer: Synapsis

Question 8. A bivalent of two homologous chromosomes has four chromatids. This is called a _________.
Answer: Tetrad

Question 9. The X-shaped structure formed due to the crossing between two non-sister chromatids of a homologous chromosome pair is called _________.
Answer: Chiasma

Question 10. The third phase of karyokinesis is called _________.
Answer: Anaphase

Question 11. Chromosomes are arranged in an equatorial line in _________ phase.
Answer: Metaphase

Question 12. Gamete formation takes place by _________ cell division.
Answer: meiosis

Question 13. The number of chromosomes is reduced in _________ phase of meiosis I.
Answer: Anaphase I

Question 14. The alternative name of crossing over is _________.
Answer: Recombination

Wbbse Class 10 Life Science Solutions

Question 15. _________ and _________ combinely formed phragmoplast.
Answer: Microfilament, Microtubule

Question 16. Interzonal fibre is formed during _________.
Answer: Anaphase

Question 17. The third phase of karyokinesis is called _________.
Answer: Anaphase

Question 18. Cytokinesis of animal cells occurs by _________.
Answer: Furrowing/ Cleavage

 

Chapter 2 Mitotic And Meiotic Cell Division State True Or False

Question 1. Mitochondria and chloroplasts can take part in spindle formation.
Answer: True

Question 2. Crossing over occurs by the exchange of segments between non-sister chromatids.
Answer: True

Question 3. Cytokinesis occurs in plant cells by cleavage.
Answer: False

Question 4. The parallel positioning of two homologous chromosomes is called a synapse.
Answer: False

Question 5. Astral ray is formed in mitosis.
Answer: True

Question 6. Spindle fibre disintegrates in metaphase.
Answer: False

Wbbse Class X Life Science

Question 7. Crossing over takes place more heterochromatin.
Answer: False

Question 8. DNA is doubled in G₂ phase.
Answer: False

Question 9. Crossing over produces variation in organisms.
Answer: True

Question 10. Only one crossing-over can takes place between two homologous chromosomes.
Answer: False

Wbbse Class 10 Life Science Solutions

Question 11. The shortest phase of cell division is prophase.
Answer: False

Question 12. Ovum is only produced as a result of mitosis.
Answer: False

 

Chapter 2 Mitotic And Meiotic Cell Division Match The Columns

1.

Answer: 1. B, 2. C, 3. D, 4. A, 5. F, 6. G

2.

Answer: 1. D, 2. A, 3. B, 4. C, 5. F, 6. G

Wbbse Class 10 Life Science Solutions

Chapter 2 Mitotic And Meiotic Cell Division Find The Odd One Out

Question 1. Condensation of chromosomes, Moving of chromosomes to the equatorial plane, Anaphasic movement of chromosomes, Formation of cell plate
Answer: Formation of cell plate

Question 2. Formation of the chiasma, Formation of the tetrad, Synapsis, and Anaphasic movement.
Answer: Anaphasic movement

Question 3. Spiralization of the chromosome, Disintegration of the nucleus, Reappearance of the nucleolus, and Spindle fibre formation.
Answer: Reappearance of the nucleolus

Question 4. Prophase, Metaphase, Telophase, Cytokinesis.
Answer: Cytokinesis

Wbbse Class 10 Life Science Solutions

Chapter 2 Mitotic And Meiotic Cell Division Fill In The Blanks By Looking At The First Pair

Question 1. The single nucleus in a cell: Prophase:: Two nuclei in a cell: _________
Answer: Telophase

Question 2. Animal cell: Cleavage:: Plant cell: _________
Answer: Cell plate

Question 3. Growth: Mitosis:: Variation: _________
Answer: Meiosis

Question 4. Chromosomal disjunction: Anaphase 1:: Crossing over: _________
Answer: Prophase I

Question 5. Prophase: Disappearance of nuclear membrane and nucleolus:: _________: Reappearance of nuclear membrane and nucleolus.
Answer: Telophase

Question 6. Synopsis: Dyad::Crossing over: _________
Answer: Tetrad

Wbbse Class 10 Life Science Solutions

Chapter 2 Mitotic And Meiotic Cell Division Among The Four Concepts Given Three Of Them Belong To One Find That

Question 1. Regeneration, Cell replacement, Mitosis, Growth.
Answer: Mitosis

Question 2. Tetrad, Crossing over, Pachytene, Chiasma.
Answer: Pachytene

Question 3. Synopsis, Prophase I, Chiasma formation, Terminalisation.
Answer: Prophase I

Question 4. Alternation of generation, Meiosis, Recombination, and Gametogenesis.
Answer: Meiosis.