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

Chapter 2 Cell Division Associating Organelles Significance Type And Cell Cycle Summary

• Cell organelle plays a major role in cell division. Most importantly nucleus is the container of chromosomes, while centrioles help to organize chromosomes before cell division, besides these functions, centrosomes and microtubules produce spindle fibre.
• Ribosomes synthesize protein and mitochondria provide ATP for the whole process of cell division. Cell division is essential for the growth, reproduction and healing process of the body.
• In living organisms, three types of cell divisions are mostly seen, These are-Amitosis, mitosis and meiosis. Amitosis are seen in the lower group of organism.
• Mitosis is responsible for growth and healing because it mainly occurs in somatic cells. Whereas meiosis takes place in gametes formation. Most importantly mitosis and meiosis are mostly found in higher order organisms.
• A series of events that takes place in the cell cyclically during its growth and division is called the cell cycle. The cell cycle is mainly divided into two phases, these are-Interphase or undivided phases and the mitotic or dividing phase.
• This interphase or undivided phase also divided into three phases-G₁. S and G₂. Cells which are going through G₁, S and G₂ phases, are prepared for cell division.
• The mitotic phase is composed of karyokinesis (a division of the nucleus) and cytokinesis (a division of the cytoplasm). Karyokinesis also occurs through certain subphases, like prophase, metaphase, anaphase and telophase.
• In the process of the cell cycle, there is a phase called G°, is a resting phase, where the cell exists in a quiescent state. By checking the physical status of the cell and the suitability of the environment for its division, the G decides whether the cell will be going to divide or stays quiescence.

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Chapter 2 Cell Division And Cell Cycle Long Answer Type Questions

Question 1. Describe different phases of the cell cycle.
Or,
What types of chemical components are synthesized in different stages of interphase in a cell cycle? What might happen if normal control at different points of a cell cycle is lost?

Answer:

Different phases of cell cycle:

The systematic and cycle of events, which continuously occurs from the end of a cell division to the end of the next cell division, is called the cell cycle. A cell cycle has two main phases-

1. Interphase:

The longer phase of a cell cycle in which a new daughter cell grows by synthesis of DNA, proteins, RNA etc. and gets all necessary cellular components to become a fully matured cell, ready for division, is called interphase.

This phase is divided into three sub-phases-G₁ or growth-1 phase, S or synthesis phase and G₂ or growth-2 phase.

1. G₁, or growth-1 phase: It is the primary phase of interphase, where rRNA, mRNA, tRNA, ribosomes and the materials necessary for DNA synthesis are produced. Doubling of various cell organelles occurs in this phase.
2. S or synthesis phase: This is the intermediate phase between G₁, and G₂ phases. During this phase, the synthesis or replication of DNA and the synthesis of histone proteins occur. Here, the DNA content of a chromosome becomes double.
3. G₂ or growth-2 phase: It is the last phase of the interphase. In this phase, the proteins, necessary for upcoming cell division, are synthesised.

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2. Mitotic phase:

It is the shortest phase of a cell cycle. This phase is divided into two sub-phases-

1. Karyokinesis, where the nucleus of a cell divides through prophase, metaphase, anaphase and telophase.
2. Cytokinesis, in which cytoplasm divides to give rise to two daughter cells.

A human needs 20-24 hours to complete a cell cycle, of which 19-23 hours go for interphase only and 1 hour for the mitotic phase.

Result of the uncontrolled cell cycle:

If for certain reasons, the checkpoints of cell cycle lost its function, then any diseased or torn-out cells can easily proceed towards cell division in an uncontrolled way and thereby give rise to cancer.

Question 2. Mention the significance of cell cycle. Write down the importance of cell division. Part Question, Analyze the role of cell divisions in controlling growth, reproduction and repair in an organism.

Answer:

Significance of cell cycle:

The significance of cell cycle is mentioned below-

1. Controlling cell division:

Certain points of the cell cycle control cell division. These are known as checkpoints. In case of any functional disruption at any of those points, the cell division process becomes uncontrolled, which may lead to tumour formation.

Tumours are of two types-benign tumour and malignant tumour. Benign tumours are harmless but malignant tumour cells invade other tissues through blood or lymph and form tumours there.

This phenomenon is called metastasis, which is a characteristic feature of cancer cells.

 

2. Normal growth and wound healing:

Cell division helps an organism to grow in size. It also assists in wound healing.

Importance of cell division:

The importance of cell cycle are given below.

1. Growth:

Number of cells of an organism increases due to cell division. The daughter cells produced by this process also grow in size. Therefore, the growth of any organism depends directly upon cell division.

2. Reproduction:

Amitosis, mitosis and meiosis help in different types of reproduction processes. Simple unicellular organisms like Amoeba, reproduce by the amitosis process. Mitosis helps in asexual and vegetative reproduction in animals and plants.

By meiotic division, gametes and spores are formed. Therefore, meiosis helps in sexual and asexual reproduction.

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3. Wound healing:

Mitosis helps in the repair of wounds and the regeneration of organs in plants and animals.

4. Transfer of genetic characters:

By cell division, the characters of the mother cell are transferred to the daughter cells. In a broader perspective, the newer characters in daughter cells help in adaptation and evolution.

Question 3. Name the cell organelles involved in cell division. Mention the role of those organelles in the cell division process.

Answer:

Cell organelles involved in cell division:

The cell organelles which are involved in the cell division process are-nucleus, centrosome, microtubules, ribosomes and mitochondria.

Role of cell organelles in cell division:

The roles of the cell organelles in cell division are discussed below.

1. Nucleus:

It carries chromosomes, which are transferred from mother cells to daughter cells along with the genetic materials during cell division.

2. Centrosome and microtubules:

In animal cells, centrosomes and in plant cells, cytoplasmic microtubules form spindle fibres during metaphase. These help in chromosomal movement during anaphase.

3. Ribosomes:

Ribosomes take part in protein synthesis. During cell division, they help in the formation of chromosomes and other cellular components, such as cell organelles, cytoplasm etc.

4 Mitochondria:

They supply the necessary energy for different activities in a dividing cell. They also regulate the cell cycle.

Chapter 2 Cell Division And Cell Cycle Short Answer Type Questions

Question 1. What is meant by cell division?

Answer:

Meaning Of Cell division:

The process, by which a fully matured cell or a mother cell divides to give rise to two or more daughter cells, is known as cell division. By means of cell division, unicellular organisms reproduce and multicellular organisms grow in size.

Question 2. How many types of cell division occur in the living world?

Answer:

Types of cell division occur in the living world:

In the living world, two main types of cell division occur. These are direct cell division and indirect cell division. Direct cell division includes amitosis.

Indirect cell division is of two types-

1. Mitosis And
2. Meiosis.

Question 3. Write down the significance of cell division.

Answer:

The significances of cell division are as follows-

1. Increasing the number of cells for the growth of an organism.
2. Production of germ cells for reproduction.
3. Healing of wounds.

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Question 4. Mention the role of mitosis in the growth of an organism.

Answer:

The role of mitosis in the growth of an organism:

As a somatic cell of an organism attains maturity, it undergoes mitosis. By this process, the number of body cells increases. As a result, the whole body of the organism grows. So, it can be said, mitosis is the cause and growth is its result.

Question 5. Mention the names of different phases of a cell cycle.

Answer:

The names of different phases of a cell cycle:

The two main phases of a cell cycle are- Interphase and mitotic phase. Interphase is sub-divided into three sub-phases, these are G₁, S and G₂, phase and the mitotic phase has two sub-phases – karyokinesis and cytokinesis.

Karyokinesis is further divided into four phases-prophase, metaphase, anaphase and telophase.

 

Question 6. What is meant by Go phase? State its by significance.

Answer:

Go phase:

In cell cycle, there is a certain point, where any change related to cell division stops completely.

G₀ is an inactive state of the cell cycle, where cells remain in a quiescent state, or else it waiting for the favourable environment or particular signal for going to the divisional phase. This phase is also known as gap phase.

Significance:

It helps to keep the cell in a quiescent State and by that way if prevents the cell from undergoing uncontrolled division. Most cells bypass this phase, but a few, like nerve cells and cardiac muscle cells, enter this phase and do not undergo any cellular division.

Question 7. What is interphase?

Answer:

Interphase:

The phase of cell cycle between the end of a cell division to the start of the next cell division, in which the growth of a daughter cell and the preparatory events for the next cell division occur, is known as interphase. Interphase is also known as the resting phase of cell cycle.

 

Question 8. Why is interphase necessary before cell division?

Answer:

During interphase, certain preparatory events occur within the cell to make it ready for division and to provide the daughter cell with their necessary cellular components. The events which occur during interphase are as follows-

1. Synthesis of DNA and certain proteins, duplication of certain cell organelles and
2. Synthesis of ATP to supply essential energy during cell division activities. Therefore, interphase is necessary before cell division.

Question 9. What is meant by mitotic cell division?

Answer:

Mitotic cell division:

Mitosis is a type of cell division, in which the mother cell divides to produce two identical daughter cells. The daughter cell contains the same number of chromosomes, like the mother cell.

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Question 10. Where does mitotic cell division occur?

Answer:

Mitotic cell division occurs in the following regions-

1. It occurs in the meristematic tissues of plants and the body cells of animals.
2. Mitosis occurs in the embryos of plants and animals during their development.
3. In unicellular organisms, mitosis occurs during vegetative and asexual reproduction.

Question 11. What is karyokinesis?

Answer:

Karyokinesis:

The word ‘karyon’ means nucleus and the word ‘kinesis’ means to move. So karyokinesis is the first and prolonged phase of mitotic division, in which the nucleus of the mother cell divides to give rise to two daughter nuclei.

Question 12. What is cytokinesis?

Answer:

Cytokinesis:

The phase of cell division, in which the cytoplasm of the mother cell divides into two halves to give rise to two daughter cells, is called cytokinesis. Cytokinesis occurs after karyokinesis.

Question 13. What do you mean by checkpoints?

Answer:

Checkpoints:

To avoid unnecessary division, three stages are there in the cell cycle at which cells are go through internal and external cues to decide, whether it will be move forward for cellular division or stay quiescent.

Generally, three checkpoints are there-G₁/S, G₂/M and the mitotic checkpoint. All these checkpoints proceed only with healthy cells towards the division and pushed torn-out cells towards apoptosis. By this process, it maintains the cellular division in a healthy way.

 

 

Question 14. State the significance of cellular checkpoints. Or, Establish the relationship between the formation of malignant tumour in the human body with the loss of control in the cell cycle.

Answer:

The significance of cellular checkpoints:

Checkpoints prevent uncontrolled cellular growth and thereby cancer. It mainly checks the genetic as well as physical integrity, if they found any genetic defect, they immediately arrest the cell from going to cellular division.

All cells will be checked by three stages. But if the genes which are responsible for the synthesis of checkpoints are mutated then they lost their control over cell division and the cells are going to divide in an uncontrolled way.

This uncontrolled cellular division gives rise to a cellular lump, called a tumour.

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Question 15. Why is mitosis called equational division?

Answer:

Mitosis called equational division:

In mitotic cell division, the number of chromosomes acquired by two daughter cells is equal to that of their mother cell.

The size and shape of those daughter cells also become identical to the mother cell. That is why, mitosis is called equational division.

Question 16. 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 17. Mention five different cell organelles taking part in the cell division process.

Answer:

Five different cell organelles taking part in the cell division process

The nucleus, centrosome, microtubules, Golgi bodies, ribosomes and mitochondria are five cell organelles taking part in cell division.

Question 18. Mention the roles of the nucleus and Golgi bodies in cell division.

Answer:

Role of the nucleus: During cell division, the chromosomes divide equally and thus distribute the genetic material within it evenly among the daughter cells.

 

 

Question 19. Mention the roles of centrosomes and microtubules in cell division.

Answer:

Role of centrosome:

In animal cells, the centrosome divides into two during prophase. Each centrosome with a pair of centrioles then moves to two opposite ends of the dividing cell to act as the poles of the spindle.

Role of microtubules:

Microtubules form the spindle fibres. These fibres attach with the centromeres of chromosomes and help them to split into daughter chromosomes during anaphase.

Question 20. Mention the role of mitochondria in cell division.

Answer:

The role of mitochondria in cell division:

Mitochondria are the powerhouse of a cell. During cell division, extra energy is needed. Mitochondria supply that energy to the dividing cell. Thus mitochondria also play an important role in controlling the cell cycle.

Question 21. Mention the role of the ribosome in cell division.

Answer:

The role of the ribosome in cell division:

Ribosomes help in the synthesis of proteins which are essential for cell division. They take part in the synthesis of enzymes necessary for protein synthesis. They also help to synthesise histone and non-histone daughter chromosomes.

Question 22. How does the absence of a centrosome affect the cell division of an animal cell?

Answer:

In animal cells, the centrosome helps in forming spindle fibres which help in chromosomal movement and it’s separation.

If there is no centrosome in an animal cell, chromosomal separation and daughter nuclei formation will not occur. As a result, cell division will not take place.

 

 

Question 23. From where do spindle fibres develop during cell division in plant and animal cells?

Answer:

During cell division in plant cells, spindle fibres develop from cytoplasmic microtubules. In animal cells, spindle fibres grow from the two centrioles, positioned at two opposite poles of the dividing cell.

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Question 24. Which problems would a multicellular organism face if mitosis stops completely?

Answer:

If mitosis stops completely, then the following complications will occur in any multicellular organism-

1. The growth and wound healing process will stop.
2. Vegetative reproduction will stop.
3. The dead and aged cells of the body will not be replenished.

Question 25. What are oncogenes?

Answer:

Oncogenes:

The genes, which transform a normal cell into a malignant cell or more simply the genes which are responsible for developing cancer, are called oncogenes.

Oncogenes are formed by mutations or by carcinogens and affect the regulatory system of cell cycle. Finally, uncontrolled cell division leads to cancer.

Question 26. What do you mean by metastasis?

Answer:

Metastasis:

Metastasis is the main characteristic of malignant tumours or cancer cells. By this process these cells can spread all over the organ of the body, not only that, it can form tumorous growth (2° tumour) of different regions of the body.

The process of spreading of cancerous cells through blood and lymph to other parts of the body is called metastasis.

Question 27. What are tumour suppressor genes? Give example.

Answer:

Tumour suppressor genes:

The genes which hinder the activity of oncogenes and thus prevent tumour formation, are called tumour suppressor genes.

Example:

p53, and pRb are tumour suppressor genes. If these genes are inactivated by any means, regulation of cell cycle disrupts and tumour formation occurs.

Question 28. What is meant by a malignant tumour?

Answer:

Malignant tumour:

Due to any irregularity in the cell cycle, normal cell division is hampered. In that case, uncontrolled cell division occurs to form a lump of cells in the body which are known as tumours.

If the tumour cells are spread through body fluids to invade other tissues of the body and form new fatal tumours, those are then called malignant tumours.

Question 29. What is amitosis?

Answer:

Amitosis:

Amitosis is a primitive type of cell division, in which the nucleus and cytoplasm divide directly into two daughter cells by simple cleavage formation without forming, a spindle apparatus Amoeba and few other unicellular organisms reproduce by amitosis.

Question 30. Mention the characteristic features of amitosis.

Answer:

The characteristic features of amitosis are as follows-

1. During amitosis, the nuclear membrane remains intact and spindle formation does not occur.
2. During this division, the nucleus develops a constriction at its centre that gives the nucleus a shape like a dumbbell.
3. The cell cytoplasm also develops a constriction at the same position as the nucleus. Both the constrictions start increasing and finally, both cytoplasm and nucleus separate into two daughter cells at a time.

Question 31. 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 32. In a human somatic cell, diploid chromosome number is 46. What will be the chromosome number of a daughter somatic cell and a gamete?

Answer:

In a human somatic cell, the diploid chromosome number is 46 (2n). The chromosome number of the daughter somatic cell will be 46 (2n). The chromosome number of the gamete will be 23 (n).

Question 33. How many nuclear divisions occur in meiosis and mention the nature of those divisions.

Answer:

During meiosis, two nuclear divisions take place. The first of these two nuclear divisions is reduction division where the number of chromosomes is reduced to half and the second one is equational division as there is no replication of the existing chromatids.

Question 34. A diploid cell contains 24 chromosomes in its nucleus. How many chromosomes will be there in the daughter cells after-

1. Mitosis,
2. Meiosis-i and
3. Meiosis-II?
4. Answer:

The diploid cell contains 2n = 24 chromosomes in its nucleus. Therefore-

1. After mitosis, the chromosome number will remain as the mother cell, i.e., 2n = 24,
2. After meiosis-I chromosome number will reduce to half the number of chromosomes in its mother cell, i.e., n = 12,
3. After meiosis-II chromosome number will remain as the daughter cells of meiosis-I, i.e., n = 12.

Question 35. What are meiocytes and meiospores?

Answer:

Meiocytes:

The diploid cells, which undergo meiotic division, are known as meiocytes.

Examples: Spermatocytes, oocytes etc.

Meiospores:

The haploid spores, which are produced from meiotic cell division, are called meiospores.

Example: Spores of ferns.

Question 36. Compare between meiosis-II And mitosis.

Answer:

Comparison between meiosis-II and mitosis are-

 

Chapter 2 Cell Division And Cell Cycle Very Short Answer Type questions Multiple Choice Questions And Answers [MCQ]

Question 1. In 1840, the process of amitosis was first described by—

1. Walther Flemming
2. Strasburger
3. Moore
4. Robert Remak

Answer: 4. Robert Remak

Question 2. The term ‘mitosis’ was first coined by—

1. Boveri
2. Moore
3. Walther Flemming
4. Remak

Answer: 3. Walther Flemming

Question 3. The cycle of events occurring after the end of one cell division to the end of next cell division is called—

1. Ornithine cycle
2. Cori cycle
3. Cell cycle
4. Krebs cycle

Answer: 3. Cell cycle

Question 4. The cell cycle is broadly divided into—

1. Two phases
2. Three phases
3. Four phases
4. Six phases

Answer: 1. Two phases

Question 5. The phase in which DNA replication occurs is called—

1. G₁phase
2. S phase
3. G₂ phase
4. M phase

Answer: 2. Two phases

Question 6. The intermediate phase of DNA synthesis and the start of the prophase is—

1. G₀ phase
2. G₁ phase
3. M phase
4. G₂ phase

Answer: 4. G₂ phase

Question 7. Interphase is placed in between—

1. Prophase and metaphase
2. Metaphase and anaphase
3. Telophase and prophase
4. Anaphase and telophase

Answer: 3. Telophase and prophase

Question 8. Which is not a character of interphase?

1. The volume of a cell increases
2. Nuclear membrane disappears
3. Energy is stored for next division
4. DNA, RNA and proteins are synthesised

Answer: 2. Nuclear membrane disappears

Question 9. In which phase of cell cycle mitosis occurs?

1. After G₁ phase
2. After S phase
3. Before G₂ phase
4. After G₂ phase

Answer: 4. After G₂phase

Question 10. In which type of cell division two daughter cells are formed with chromosome numbers identical to the mother cell?

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

Answer: 2. Mitosis

Question 11. The phase of cel! cycle, in which cell division-related activities are completely stopped, is called—

1. G₁ phase
2. G₂ phase
3. S phase
4. G₀ phase

Answer: 4. G₀ phase

Question 12. The phase of cell division in which counting the number of chromosomes becomes the easiest is—

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

Answer: 2. Metaphase

Question 13. Meiotic cell division is also called—

1. Equal division
2. Multiple division
3. Unequal division
4. Reduction division

Answer: 4. Reduction division

Question 14. Which of the following will you not draw in the diagram of a prokaryotic cell?

1. Mitochondria
2. Chromatophore
3. Mesosome
4. Nucleoid

Answer: 1. Mitochondria

Question 15. The phase in between two successive cell divisions is called—

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

Answer: 2. Interphase

Question 16. Bacterial cell division is called—

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

Answer: 2. Amitosis

Question l7. The chromosome number of an organism is 2n=24. What will be the chromosome number of its sperms or ova?

1. 6
2. 12
3. 18
4. 24

Answer: 2. 12

Question 18. The disease caused due to uncontrolled cell cycle is—

1. Cancer
2. Malaria
3. Cirrhosis
4. Tuberculosis

Answer: 1. Cancer

Question 19. Which of the following is called direct cell division?

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

Answer: 3. Amitosis

Question 20. The mode of reproduction in unicellular organisms is—

1. Somatic cell formation
2. Cell cycle
3. Cell membrane formation
4. Cell division

Answer: 4. Cell division

Question 21. Which of the following helps in movement of chromosomes during cell division?

1. Spindle fibre
2. Cytoplasm
3. Ribosome
4. Mitochondria

Answer: 1. Spindle fibre

Question 22. Which of the following supplies energies during cell division?

1. Centrosome
2. Cytoplasm
3. Ribosome
4. Mitochondria

Answer: 4. Mitochondria

Question 23. Who coined the term amitosis?

1. Walther Flemming
2. Strasuburger
3. Robert Remauk
4. Robert Hook

Answer: 1. Walther Flemming

Question 24. Which of the following is a direct cell division?

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

Answer: 4. Amitosis

Question 25. In which type of cell division metaphase does not take place?

1. Mitosis
2. Amitosis
3. Meiosis
4. None of the above

Answer: 2. Amitosis

Question 26. Meiosis is—

1. Equational division
2. Multiple fission
3. Reductional division
4. Unequal division

Answer: 3. Reductional division

Question 27. In which of the following phase cell can not divide?

1. G₁
2. G₂
3. S
4. G₀

Answer: 4. G₀

Question 28. Which of the following sequence is right?

1. G₁— s—M— G₂
2. G₁—S—G₂—M
3. G₁—G₂—S—M
4. M— G₁—S— G₂

Answer: 2. GJ—S—G₂—M

Question 29. Which of the following is not a character of Interphase?

1. Increase in volume of cell
2. The disintegration of nuclear membrane
3. Energy production
4. DNA production

Answer: 2. Disintegration of the nuclear membrane

Question 30. On which of the following organism amitosis takes place?

1. Human
2. Amoeba
3. Frog
4. Mango plant

Answer: 2. Amoeba

Question 31. Determine the number of DNA molecules that get coiled to form each chromosome in a newly formed daughter cell produced by mitotic cell division in the human body.

1. 46
2. 1
3. 23
4. Numerous

Answer: 2. 1

 

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

Question 1. By which process two or more daughter cells develop from a single cell?
Answer: Cell division

Question 2. How much increase in DNA content within the nucleus initiates cell division?
Answer: When the content of DNA within a nucleus becomes double, cell division is initiated.

Question 3. Which organic matter initiates cell division process in plant and animal bodies?
Answer: Specific protein factors or growth hormones in animal and plant bodies initiate cell division.

Question 4. Name two compounds which prevent cell division.
Answer: Azides and cyanides

Question 5. What is karyokinesis?
Answer: Nuclear division within a cell is called karyokinesis.

Question 6. What is cytokinesis?
Answer: Splitting up of the cytoplasm in a dividing cell is called cytokinesis.

Question 7. Where does amitotic cell division occur?
Answer: Amitotic cell division occurs in lower groups of organisms like bacteria, yeast, an alga named Chara etc.

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Question 8. Name two animal cells which remain in G₀ phase.
Answer: Nerve cells and cardiac muscle

Question 9. In which phase of cell cycle does DNA synthesis occur?
Answer: In the S phase

Question 10. The somatic cell of a plant carries 14 chromosomes. After mitotic division, how many chromosomes will be there in the daughter cell?
Answer: If the somatic cell of a plant carries 14 chromosomes, then after mitosis the daughter cell will also carry chromosomes.

Question 11. Why nerve cells do not undergo cell division?
Answer: Since nerve cells possess inactive centrosomes which are unable to produce spindle, so these cells do not undergo cell division.

Question 12. What type of cell division is the binary fission of Amoeba?
Answer: Binary fission of Amoeba is an amitotic cell division.

Question 13. Which cell organelle supplies energy for human cell division?
Answer: Mitochondrion

Question 14. Name a cell organelle that increases in number during the G₂ phase.
Answer: Mitochondrion is the cell organelle which increases in number during the G₂ phase.

Question 15. How many daughter cells will be available after five consecutive mitotic divisions of an animal cell?
Answer: After five consecutive mitotic divisions of an animal cell, 32 daughter cells will be available.

Question 16. Which substance produce spindle fibre in blant cell?
Answer: Microtuble

Question 17. What is the role of the centrosome in animal cell division?
Answer: Centrosomes produce spindle fibres during cell division in animal cells.

Question 18. Which cell organelle supplies phospholipids during membrane formation in cell division?
Answer: Smooth endoplasmic reticulum

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Question 19. Write down the name of a substance helping in cell division.
Answer: Growth hormone

Question 20. In which type of cell division chromosome is not seen?
Answer: Amitosis

Question 21. What type of cell division is the binary fission of Amoeba?
Answer: Amitosis

Question 22. Which type of cell division helps in the healing of the body?
Answer: Mitosis

Question 23. Which phase of cell division is called the quiescent phase?
Answer: Go phase

Question 24. Name two cells which are present permanently in Go stage.
Answer: Nerve cells and Muscle cells of the heart.

Question 25. Name one enzyme controlling cell cycle.
Answer: Cyclin Dependent Kinase (CDK).

Question 26. How many cells will be produced if a cell undergoes five mitotic divisions successively?
Answer: 32

Question 27. Which is the longest and shortest phase of Interphase?
Answer: Longest phase-G₁, shortest phase-G₂

 

Chapter 2 Cell Division And Cell Cycle Fill In The Blanks

Question 1. The whole body of an organism is formed from a single _______.
Answer: cell

Question 2. The process of synthesis of DNA from another DNA is called _______.
Answer: Replication

Question 3. The membrane-less cytoplasmic organelle that plays an important role in protein synthesis is known as _______.
Answer: Ribosome

Question 4. Energy generated within mitochondria remains stored in _______ molecules.
Answer: ATP

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Question 5. _______ cell division is called equational division.
Answer: Mitotic

Question 6. Amitosis is a _______ cell division.
Answer: Direct

Question 7. Meiosis it is a _______ division.
Answer: Equational

Question 8. Cell organelles become doubled in phase.
Answer: G

Question 9. DNA synthesis takes place in _______ phase of the cell cycle.
Answer: S

Question 10. _______ phase of cell division is called the dormant phase.
Answer: Go phase

 

Chapter 2 Cell Division And Cell Cycle State True Or False

Question 1. Ribosome helps in protein synthesis.
Answer: True

Question 2. Uncontrolled cell division results in to cancer.
Answer: True

Question 3. The go stage is seen in all somatic cells.
Answer: False

Question 4. Mitochondria supply the necessary energy for cell division.
Answer: True

Wbbse Class 10 Life Science Solutions

Question 5. Amitotic cell division occurs in neurone.
Answer: False

Question 6. Mitotic cell division occurs in the germ mother cell.
Answer: False

Question 7. Chromosome number decreases in daughter cells after meiosis.
Answer: True

Question 8. The mitotic division is known as the equational division.
Answer: True

Question 9. Meiosis plays important role in the alternation of generations.
Answer: True

 

Chapter 2 Cell Division And Cell Cycle Match The Columns

1.

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

2.

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

Chapter 2 Cell Division And Cell Cycle Find The Odd One Out

Question 1. Spindle fibre formation, Energy generation, Protein production, O₂ conduction
Answer: Oxygen conduction

Question 2. Amitosis, Direct cell division, Amoeba, Human
Answer: Human

Question 3. Reductional division, Gamete formation, Crossing over, Somatic cell formation
Answer: Somatic cell formation

Question 4. Interphase, Metaphase, Anaphase, Prophase
Answer: Interphase

Wbbse Class 10 Life Science Solutions

Question 5. G₁, S, G₂, M
Answer: M

Question 6. Cell number increase, Healing, Reproduction, Circulation
Answer: Circulation

Question 7. Uncontrolled cell division, Tumour formation, RBC formation, Cancer
Answer: RBC formation

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

Question 1. Mitochondria: Energy supply in cell division:: Centrosome: __________.
Answer: spindle fibre formation

Question 2. Spindle fibre formation in animal cell : Centrosome: Spindle fibre formation in plant cell: __________.
Answer: Microtubule

Question 3. Mitosis: equational division:: Meiosis: __________.
Answer: Reductional division

Question 4. Somatic cell formation: Mitosis :: Gamete formation: __________.
Answer: Meiosis

Question 5. Sperm formation: Mitosis: Growth of embryo: __________.
Answer: Mitosis

Wbbse Class 10 Life Science Solutions

Question 6. G phase: Interphase :: Metaphase: __________.
Answer: M phase

Question 7. Mitosis: Radicle:: __________:Spore mother cell.
Answer: Meiosis

Question 8. Mitosis: Radicle :: Meiosis __________.
Answer: Spore mother cell

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

Question 1. Yeast, Paramoecium, Amitosis, Bacteria
Answer: Amitosis

Question 2. Growth of embryo, Spore mother cell formation, Mitosis, Healing
Answer: Mitosis

Question 3. G₁, phase, S phase, Interphase, G₂ phase
Answer: Interphase

Question 4. Ribose sugar, Phosphate, N₂ base, RNA.
Answer: RNA

Wbbse Class 10 Life Science Solutions

Question 5. Sperm production, Egg production, Meiosis, Pollen formation
Answer: Meiosis

Question 6. N₂ base, DNA, phosphate, Deoxyribose sugar
Answer: DNA

Question 7. H2A, H2B, H4, Histone
Answer: Histone