Cell Cycle and Cell Division

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Learning Objectives

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Learning Objectives

Describe the stages of the cell cycle and their significance.
Explain the process and significance of mitosis.
Differentiate between mitosis and meiosis.
Identify the stages of meiosis and their key events.
Discuss the significance of meiosis in genetic variability.
Analyze the differences in cytokinesis between plant and animal cells.
Illustrate the events occurring during each phase of the cell cycle.
Define key terms such as synapsis, bivalent, and chiasmata.

Revision Notes & Summary

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Chapter 10: Cell Cycle and Cell Division

10.1 Cell Cycle

Definition: Sequence of events by which a cell duplicates its genome, synthesizes other constituents, and divides into two daughter cells.
Phases:
- Interphase: Preparation for cell division, further divided into:
  - G₁ Phase: Cell growth and normal metabolism.
  - S Phase: DNA replication and chromosome duplication.
  - G₂ Phase: Cytoplasmic growth.
- M Phase (Mitosis): Actual cell division, divided into four stages:
  - Prophase: Chromosomes condense, centrioles move to poles.
  - Metaphase: Chromosomes align at the equatorial plate.
  - Anaphase: Centromeres split, chromatids move to opposite poles.
  - Telophase: Chromosomes decondense, nuclear envelope reforms.

10.2 M Phase

Karyokinesis: Nuclear division, includes four stages:
- Prophase: Chromosomal material condenses.
- Metaphase: Chromosomes align at the metaphase plate.
- Anaphase: Chromatids separate and move to poles.
- Telophase: Nuclear envelope reforms around chromosome clusters.
Cytokinesis: Division of cytoplasm, differs in plant and animal cells.

10.3 Significance of Mitosis

Equational Division: Produces diploid daughter cells with identical genetic material.
Growth and Repair: Essential for growth of multicellular organisms and repair of tissues.

10.4 Meiosis

Definition: Specialized cell division that reduces chromosome number by half, producing haploid cells.
Phases:
- Meiosis I: Homologous chromosomes pair and undergo crossing over.
- Meiosis II: Similar to mitosis, sister chromatids separate.
Significance: Ensures genetic diversity and conservation of chromosome number across generations.

10.5 Significance of Meiosis

Genetic Variability: Increases genetic diversity in populations, crucial for evolution.
Haploid Gametes: Formation of gametes for sexual reproduction.

Key Events in Meiosis I

Prophase I: Chromosomes condense, homologous chromosomes pair (synapsis).
Metaphase I: Bivalents align at the equatorial plate.
Anaphase I: Homologous chromosomes separate to opposite poles.
Telophase I: Two new cells form, each with one set of chromosomes.

Diagram Descriptions

Stages of Meiosis I: Illustrates Prophase I, Metaphase I, Anaphase I, and Telophase I with key events labeled.
Cell Cycle Phases: Circular chart showing G₀, Interphase (G₁, S, G₂), and M Phase with detailed stages of mitosis.
Mitosis Stages: Diagrams depicting Prophase, Metaphase, Anaphase, and Telophase with labeled features.

Exam Tips & Common Mistakes

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Common Mistakes and Exam Tips

Common Pitfalls

Confusing Mitosis and Meiosis: Students often mix up the stages and processes of mitosis and meiosis. Remember that mitosis is equational division resulting in two identical diploid cells, while meiosis is reductional division resulting in four genetically diverse haploid cells.
Overlooking the Importance of Interphase: Many students forget that interphase is crucial for DNA replication and cell growth before mitosis or meiosis occurs. Ensure to understand the phases of interphase (G₁, S, G₂) and their significance.
Misunderstanding Cytokinesis: Students may confuse cytokinesis with karyokinesis. Karyokinesis refers to the division of the nucleus, while cytokinesis is the division of the cytoplasm.
Ignoring the Role of Chromosomes: Failing to recognize the significance of chromosome behavior during different phases can lead to errors. For example, during anaphase I of meiosis, homologous chromosomes separate, while sister chromatids remain together.

Tips for Success

Diagram Practice: Regularly practice drawing and labeling the stages of mitosis and meiosis. Visual aids can help solidify your understanding of the processes.
Use Mnemonics: Create mnemonics to remember the order of phases in both mitosis and meiosis. For example, for meiosis I: Prophase, Metaphase, Anaphase, Telophase (PMAT).
Focus on Key Differences: Make a chart comparing mitosis and meiosis, highlighting key differences such as the number of divisions, chromosome number, and genetic variability.
Discuss with Peers: Engage in group discussions to clarify doubts and reinforce learning. Teaching concepts to others can enhance your understanding.
Review Past Exam Questions: Familiarize yourself with common exam questions related to the cell cycle and division processes to better prepare for assessments.

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Practice Test – MCQs, True/False

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Multiple Choice Questions

To produce gametes

To increase genetic diversity

To facilitate growth and repair

To reduce chromosome number

Correct Answer: C

Solution:

Mitosis is responsible for growth and repair in multicellular organisms by producing identical daughter cells.

Cleavage furrow

Cell plate

Spindle fibers

Nuclear envelope

Correct Answer: B

Solution:

In plant cells, cytokinesis occurs through the formation of a cell plate, which develops at the center and grows outward to divide the cell.

Animal cells form a cell plate; plant cells form a cleavage furrow

Plant cells form a cell plate; animal cells form a cleavage furrow

Both plant and animal cells form a cell plate

Both plant and animal cells form a cleavage furrow

Correct Answer: B

Solution:

In plant cells, cytokinesis occurs through the formation of a cell plate, which develops into a new cell wall. In contrast, animal cells undergo cytokinesis by forming a cleavage furrow.

It reduces the chromosome number by half

It produces genetically identical diploid daughter cells

It increases genetic variability

It occurs only in haploid cells

Correct Answer: B

Solution:

Mitosis is significant in multicellular organisms as it produces genetically identical diploid daughter cells, aiding in growth and repair.

Prophase; Centrioles

Metaphase; Spindle fibers

Anaphase; Chromatids

Telophase; Nuclear envelope

Correct Answer: B

Solution:

During metaphase, chromosomes align at the equatorial plate, and spindle fibers attached to kinetochores are responsible for their movement.

Mitosis

Cytokinesis

Meiosis

Binary fission

Correct Answer: C

Solution:

Meiosis increases genetic variability through processes such as crossing over and independent assortment of chromosomes, which occur during meiosis I. This genetic variability is crucial for evolution and adaptation in sexually reproducing organisms.

Prophase

Metaphase

Anaphase

Telophase

Correct Answer: B

Solution:

In metaphase, the chromosomes are fully condensed and align at the equatorial plate, making them most suitable for morphological studies.

Prophase

Metaphase

Anaphase

Telophase

Correct Answer: B

Solution:

During metaphase, chromosomes align at the equatorial plate, preparing for separation.

Prophase I

Metaphase I

Anaphase I

Telophase I

Correct Answer: A

Solution:

During prophase I of meiosis, homologous chromosomes pair and undergo crossing over, which is crucial for genetic recombination.

By maintaining the chromosome number

By producing identical daughter cells

Through crossing over and independent assortment

By doubling the chromosome number

Correct Answer: C

Solution:

Meiosis contributes to genetic variation through crossing over during Prophase I and independent assortment of chromosomes during Metaphase I, leading to new combinations of alleles in gametes.

Chromosomes condense and become visible

Chromosomes align at the equatorial plate

Chromosomes cluster at opposite spindle poles

Chromatids separate and move to opposite poles

Correct Answer: C

Solution:

In telophase, chromosomes cluster at opposite spindle poles, and the nuclear envelope reforms.

It involves the formation of a cleavage furrow.

It involves the formation of a cell plate.

It occurs through binary fission.

It does not involve spindle fibers.

Correct Answer: B

Solution:

In plant cells, cytokinesis occurs by forming a cell plate that grows outward to meet the existing cell walls, unlike the cleavage furrow in animal cells.

G1 phase

S phase

G2 phase

M phase

Correct Answer: B

Solution:

DNA replication occurs during the S phase of the cell cycle.

To increase the number of chromosomes

To produce diploid gametes

To reduce the chromosome number by half

To repair damaged cells

Correct Answer: C

Solution:

Meiosis reduces the chromosome number by half, producing haploid gametes, which is essential for maintaining the species' chromosome number through sexual reproduction.

Cleavage furrow

Cell plate

Spindle apparatus

Synaptonemal complex

Correct Answer: B

Solution:

In plant cells, cytokinesis occurs through the formation of a cell plate, which develops into a new cell wall.

Prophase

Metaphase

Anaphase

Telophase

Correct Answer: B

Solution:

During metaphase, chromosomes are fully condensed and aligned at the metaphase plate, making them most easily visible under a microscope.

Cell plate

Cleavage furrow

Spindle fibers

Centrosome

Correct Answer: A

Solution:

In plant cells, the cell plate forms during cytokinesis and eventually develops into a new cell wall, separating the two daughter cells.

G₁ Phase

S Phase

G₂ Phase

M Phase

Correct Answer: B

Solution:

The S phase of the cell cycle is when DNA replication occurs, resulting in the duplication of chromosomes.

Chromosomes align at the equatorial plate

Homologous chromosomes pair and form synaptonemal complexes

Centromeres split and chromatids separate

Nuclear envelope reforms

Correct Answer: B

Solution:

During prophase I of meiosis, homologous chromosomes pair and form synaptonemal complexes, a process known as synapsis.

Prophase I

Metaphase I

Anaphase I

Telophase I

Correct Answer: A

Solution:

Crossing over occurs during Prophase I of meiosis, specifically in the pachytene stage, where homologous chromosomes exchange genetic material.

Chromosomes align at the equator

Nuclear envelope disintegrates

Centromeres split and chromatids separate

Chromosomes decondense

Correct Answer: C

Solution:

Anaphase begins when the centromeres split and the sister chromatids are pulled apart to opposite poles of the cell.

Chromosomes align at the equatorial plate.

Nuclear envelope reappears.

Centromeres split and chromatids separate.

Chromosomes decondense.

Correct Answer: C

Solution:

During anaphase, the centromeres split, and the sister chromatids, now individual chromosomes, move to opposite poles of the cell.

Leptotene

Zygotene

Pachytene

Diplotene

Correct Answer: B

Solution:

During the zygotene stage of prophase I in meiosis, homologous chromosomes pair up, and the synaptonemal complex forms, facilitating synapsis.

Prophase

Metaphase

Anaphase

Telophase

Correct Answer: C

Solution:

Anaphase is characterized by the splitting of centromeres and the movement of chromatids to opposite poles.

It reduces the chromosome number by half.

It results in genetic variation.

It produces identical diploid daughter cells for growth and repair.

It occurs only in gametes.

Correct Answer: C

Solution:

Mitosis is crucial for growth and repair in multicellular organisms as it produces diploid daughter cells that are genetically identical to the parent cell.

Chromosomes align at the equatorial plate

Chromatids separate and move to opposite poles

Chromosomes cluster at opposite spindle poles and lose their identity

Nuclear envelope disintegrates

Correct Answer: C

Solution:

Telophase begins when chromosomes cluster at opposite spindle poles and lose their identity as discrete elements.

Prophase

Metaphase

Anaphase

Telophase

Correct Answer: D

Solution:

During telophase, the chromosomes reach the opposite poles of the cell and begin to decondense. The nuclear envelope reappears around each set of chromosomes, and the nucleolus becomes visible again, marking the end of mitosis.

Chromosomes condense and become visible.

Chromosomes align at the metaphase plate.

Centromeres split and chromatids move to opposite poles.

Nuclear envelope re-forms around chromosome clusters.

Correct Answer: C

Solution:

During anaphase, the centromeres split, and the sister chromatids, now individual chromosomes, move to opposite poles of the cell.

To replicate DNA

To separate sister chromatids

To divide the cytoplasm and form two daughter cells

To condense chromosomes

Correct Answer: C

Solution:

Cytokinesis is the process that divides the cytoplasm, resulting in two separate daughter cells.

Prophase

Metaphase

Anaphase

Telophase

Correct Answer: B

Solution:

During metaphase, chromosomes align at the equatorial plate, and spindle fibers attach to the kinetochores of the chromosomes.

Formation of a cleavage furrow

Formation of a cell plate

Chromosome condensation

Spindle fiber formation

Correct Answer: B

Solution:

In plant cells, cytokinesis occurs through the formation of a cell plate, which eventually develops into a separating wall.

To condense chromosomes

To separate chromatids

To form the nuclear envelope

To dissolve the nucleolus

Correct Answer: B

Solution:

Spindle fibers attach to kinetochores and help separate chromatids during mitosis.

Animal cells form a cell plate; plant cells form a cleavage furrow

Plant cells form a cleavage furrow; animal cells form a cell plate

Animal cells form a cleavage furrow; plant cells form a cell plate

Both plant and animal cells form a cleavage furrow

Correct Answer: C

Solution:

In animal cells, cytokinesis occurs through the formation of a cleavage furrow, while in plant cells, a cell plate forms to divide the cytoplasm.

To condense chromatin

To attach to kinetochores and align chromosomes at the equatorial plate

To dissolve the nuclear envelope

To separate sister chromatids

Correct Answer: B

Solution:

During metaphase, spindle fibers attach to the kinetochores of chromosomes and help align them at the equatorial plate. This alignment is crucial for the equal distribution of chromosomes into the daughter cells during anaphase.

To reduce chromosome number by half

To produce genetically identical daughter cells

To facilitate genetic variation

To form gametes

Correct Answer: B

Solution:

Mitosis results in the production of genetically identical daughter cells, which is crucial for growth and repair in multicellular organisms.

Prophase I; it facilitates crossing over

Metaphase I; it aligns homologous chromosomes

Anaphase I; it separates homologous chromosomes

Telophase I; it forms the nuclear envelope

Correct Answer: A

Solution:

During Prophase I of meiosis, the synaptonemal complex forms, allowing homologous chromosomes to undergo synapsis and facilitate crossing over, which is crucial for genetic recombination.

It doubles the chromosome number in gametes.

It ensures genetic uniformity across generations.

It reduces the chromosome number by half and increases genetic variability.

It results in the production of diploid gametes.

Correct Answer: C

Solution:

Meiosis reduces the chromosome number by half, producing haploid gametes, and increases genetic variability through recombination and independent assortment.

Plant cells form a cleavage furrow, while animal cells form a cell plate.

Animal cells form a cleavage furrow, while plant cells form a cell plate.

Both plant and animal cells form a cell plate.

Both plant and animal cells form a cleavage furrow.

Correct Answer: B

Solution:

In animal cells, cytokinesis is achieved by the formation of a cleavage furrow. In contrast, plant cells form a cell plate that eventually develops into a separating wall.

Prophase

Metaphase

Anaphase

Telophase

Correct Answer: B

Solution:

During metaphase, the chromosomes align at the equatorial plate, making it the most suitable stage for studying chromosome morphology.

It assists in the separation of sister chromatids.

It facilitates the pairing of homologous chromosomes.

It forms the spindle apparatus.

It triggers the onset of cytokinesis.

Correct Answer: B

Solution:

The synaptonemal complex is a protein structure that forms between homologous chromosomes during meiosis and facilitates their pairing and recombination.

Chromosomes align at the equatorial plate

Chromatids separate and move to opposite poles

Nuclear envelope reforms

Chromosomes condense

Correct Answer: B

Solution:

During anaphase, the centromeres split and the chromatids, now individual chromosomes, move to opposite poles.

Spindle fibers

Nuclear envelope and nucleolus

Centromeres

Kinetochores

Correct Answer: B

Solution:

During telophase, the nuclear envelope and nucleolus reappear as the chromosomes begin to decondense.

It is a phase of active cell division

It is a phase of DNA replication

It is a resting phase where cells do not divide

It is a phase of rapid cell growth

Correct Answer: C

Solution:

The G₀ phase is a quiescent stage where cells are metabolically active but do not divide.

Prophase I

Metaphase I

Anaphase I

Telophase I

Correct Answer: A

Solution:

During prophase I of meiosis, homologous chromosomes pair up in a process called synapsis and exchange genetic material through crossing over.

G1 phase

S phase

G2 phase

M phase

Correct Answer: B

Solution:

DNA replication occurs during the S phase of interphase, preparing the cell for subsequent division.

To produce haploid gametes

To increase genetic diversity

To repair and replace damaged cells

To reduce chromosome number by half

Correct Answer: C

Solution:

Mitosis is primarily responsible for growth and repair in multicellular organisms by producing identical diploid daughter cells.

G₁ Phase

S Phase

G₂ Phase

M Phase

Correct Answer: B

Solution:

The S phase, or synthesis phase, of the cell cycle is characterized by the replication of DNA. During this phase, each chromosome is duplicated to ensure that both daughter cells receive an identical set of chromosomes.

Prophase; kinetochores and spindle fibers

Metaphase; kinetochores and spindle fibers

Anaphase; centromeres and spindle fibers

Telophase; nuclear envelope and nucleolus

Correct Answer: B

Solution:

During metaphase, chromosomes align at the equatorial plate. The kinetochores on the centromeres of the chromosomes are attached to spindle fibers, which help in positioning the chromosomes.

Cleavage furrow

Cell plate

Spindle fibers

Centrosome

Correct Answer: B

Solution:

In plant cells, cytokinesis is achieved by the formation of a cell plate. This structure forms at the center of the cell and grows outward to meet the existing cell walls, thereby dividing the cytoplasm into two daughter cells.

To produce diploid cells

To increase genetic variability

To repair damaged cells

To produce identical daughter cells

Correct Answer: B

Solution:

Meiosis increases genetic variability and reduces chromosome number by half, essential for sexual reproduction.

Chromosomes condense and become visible

Chromosomes align at the equatorial plate

Chromatids separate and move to poles

Nuclear envelope re-forms

Correct Answer: B

Solution:

During metaphase, chromosomes align at the equatorial plate, making it a key feature of this stage.

It produces diploid cells

It conserves the chromosome number across generations

It repairs damaged cells

It occurs in somatic cells

Correct Answer: B

Solution:

Meiosis is significant because it reduces the chromosome number by half, ensuring that the chromosome number is conserved across generations when gametes fuse during fertilization.

True or False

Correct Answer: False

Solution:

Meiosis results in the production of haploid daughter cells, reducing the chromosome number by half.

Correct Answer: True

Solution:

The S phase of interphase marks the phase of DNA replication and chromosome duplication.

Correct Answer: True

Solution:

In telophase, chromosomes that have reached their respective poles decondense and lose their individuality, forming chromatin material.

Correct Answer: True

Solution:

In telophase, the chromosomes that have reached their respective poles decondense and the nuclear envelope reforms around the chromosome clusters, forming two daughter nuclei.

Correct Answer: True

Solution:

During prophase I of meiosis, homologous chromosomes pair up in a process called synapsis and exchange genetic material through crossing over.

Correct Answer: True

Solution:

In telophase, chromosomes reach their respective poles and decondense, losing their individuality.

Correct Answer: False

Solution:

In plant cells, cytokinesis involves the formation of a cell plate, not a furrow, due to the presence of a rigid cell wall.

Correct Answer: False

Solution:

Meiosis results in the production of haploid daughter cells, reducing the chromosome number by half.

Correct Answer: True

Solution:

In plant cells, cytokinesis is achieved by the formation of a cell-plate that starts in the center of the cell and extends outward to fuse with the cell wall, dividing the cell into two.

Correct Answer: True

Solution:

Mitosis results in the production of identical daughter cells, which are essential for the growth and repair of tissues in multicellular organisms.

Correct Answer: True

Solution:

During metaphase, chromosomes align at the equatorial plane known as the metaphase plate.

Correct Answer: True

Solution:

The G₀ phase is a quiescent stage where cells remain metabolically active but do not undergo division unless triggered by specific signals.

Correct Answer: True

Solution:

In plant cells, cytokinesis involves the formation of a cell plate that grows outward to meet the existing cell walls.

Correct Answer: False

Solution:

Mitosis is called equational division because it results in daughter cells that have the same number of chromosomes as the parent cell, not half.

Correct Answer: True

Solution:

During the S phase of the cell cycle, DNA synthesis occurs, leading to the replication of chromosomes.

Correct Answer: True

Solution:

During telophase, once the chromatids reach the two poles, the chromosomal elongation starts, and the nucleolus and the nuclear membrane reappear.

Correct Answer: False

Solution:

Mitosis usually occurs in diploid somatic cells in animals, although there are exceptions in some haploid cells like male honey bees.

Correct Answer: True

Solution:

In telophase, the chromosomes that have reached their respective poles decondense and lose their individuality, making them indistinct.

Correct Answer: True

Solution:

Prophase is marked by the disappearance of the nucleolus and the nuclear envelope as the spindle fibres start appearing.

Correct Answer: True

Solution:

Meiosis increases genetic variability through recombination and independent assortment, which are crucial for evolution.

Correct Answer: True

Solution:

During metaphase, chromosomes align at the equator of the cell, forming the metaphase plate.

Correct Answer: False

Solution:

Mitosis usually results in the production of diploid daughter cells with identical genetic complement.

Correct Answer: True

Solution:

The complete disintegration of the nuclear envelope marks the start of metaphase, allowing chromosomes to spread through the cytoplasm.

Correct Answer: True

Solution:

During metaphase, chromosomes align at the equatorial plate, with spindle fibers attaching to their kinetochores.

Correct Answer: True

Solution:

In meiosis, homologous chromosomes pair during prophase I and undergo recombination, which increases genetic variability.

Correct Answer: True

Solution:

Meiosis involves two rounds of division, resulting in four haploid cells from one diploid cell, which is crucial for sexual reproduction.

Correct Answer: True

Solution:

Meiosis consists of two sequential cycles of nuclear and cell division: meiosis I and meiosis II.

Correct Answer: False

Solution:

In animal cells, cytokinesis is achieved by the formation of a cleavage furrow, not a cell plate. The cell plate formation is characteristic of plant cells.

Correct Answer: False

Solution:

Meiosis results in the formation of four haploid cells, not diploid.

Correct Answer: False

Solution:

Mitosis usually results in the production of diploid daughter cells with identical genetic complement.

Correct Answer: False

Solution:

While mitosis is usually restricted to diploid cells, in some lower plants and social insects, haploid cells also divide by mitosis.

Correct Answer: True

Solution:

In plant cells, cytokinesis occurs through the formation of a cell plate that develops into a new cell wall, separating the two daughter cells.

Correct Answer: True

Solution:

In metaphase, chromosomes are aligned at the cell's equatorial plate, with spindle fibers attaching to the kinetochores of each chromosome, facilitating their movement.

Correct Answer: False

Solution:

In animal cells, cytokinesis is achieved by the formation of a furrow in the plasma membrane, not a cell plate.

Correct Answer: True

Solution:

Meiosis involves two sequential cycles of nuclear and cell division called meiosis I and meiosis II but only a single cycle of DNA replication.

Correct Answer: True

Solution:

Mitosis is called equational division because it results in daughter cells with the same chromosome number as the parent cell.

Correct Answer: True

Solution:

Meiosis consists of two divisions (meiosis I and meiosis II) without an intervening round of DNA replication, ensuring the production of haploid cells.

Correct Answer: True

Solution:

In metaphase, chromosomes align at the equatorial plate, which is a key feature of this stage.

Correct Answer: False

Solution:

While mitosis is usually restricted to diploid cells, it can also occur in haploid cells in some lower plants and social insects.

Correct Answer: False

Solution:

Mitosis typically results in the production of diploid daughter cells that are genetically identical to the parent cell.

Correct Answer: True

Solution:

In plant cells, cytokinesis occurs through the formation of a cell plate, which develops into a new cell wall, separating the two daughter cells.

Correct Answer: True

Solution:

In telophase, chromosomes that have reached their respective poles decondense and lose their individuality, forming two daughter nuclei.

Correct Answer: True

Solution:

During telophase, the nucleolus reappears as the chromosomes begin to decondense and the nuclear envelope reforms around the daughter nuclei.

Correct Answer: True

Solution:

In metaphase, chromosomes align at the equatorial plate with spindle fibers attached to kinetochores.

Correct Answer: True

Solution:

Anaphase is characterized by the splitting of centromeres and the movement of daughter chromatids towards opposite poles.

Correct Answer: False

Solution:

In animal cells, cytokinesis is achieved by the appearance of a furrow in the plasma membrane, not a cell plate.

Correct Answer: True

Solution:

In anaphase, each chromosome arranged at the metaphase plate is split, and the two daughter chromatids begin their migration towards the two opposite poles.

Correct Answer: False

Solution:

While mitosis is usually restricted to diploid cells, it can also occur in haploid cells in some lower plants and social insects.

Correct Answer: True

Solution:

In anaphase, each chromosome arranged at the metaphase plate is split simultaneously, and the two daughter chromatids, now referred to as daughter chromosomes, begin their migration towards the two opposite poles.

Cell Cycle and Cell Division

Learning Objectives

Learning Objectives

Revision Notes & Summary

Chapter 10: Cell Cycle and Cell Division

10.1 Cell Cycle

10.2 M Phase

10.3 Significance of Mitosis

10.4 Meiosis

10.5 Significance of Meiosis

Key Events in Meiosis I

Diagram Descriptions

Exam Tips & Common Mistakes

Common Mistakes and Exam Tips

Common Pitfalls

Tips for Success

AI Learning Assistant

Practice Test – MCQs, True/False

Multiple Choice Questions

Q1.What is the primary function of mitosis in multicellular organisms?

Correct Answer: C

Q2.In plant cells, what structure forms during cytokinesis to separate the two daughter cells?

Correct Answer: B

Q3.In plant cells, how does cytokinesis differ from that in animal cells, and what structure is primarily involved?

Correct Answer: B

Q4.What is the significance of mitosis in multicellular organisms?

Correct Answer: B

Q5.During which phase of mitosis do chromosomes align at the equatorial plate, and what structure is responsible for their movement?

Correct Answer: B

Q6.Which of the following processes increases genetic variability in sexually reproducing organisms?

Correct Answer: C

Q7.During which stage of mitosis do the chromosomes align at the equatorial plate and become most suitable for morphological studies?

Correct Answer: B

Q8.During which phase of mitosis do the chromosomes align at the equatorial plate?

Correct Answer: B

Q9.In which phase of meiosis do homologous chromosomes pair and undergo crossing over?

Correct Answer: A

Q10.How does meiosis contribute to genetic variation in sexually reproducing organisms?

Correct Answer: C

Q11.Which of the following events occurs during telophase of mitosis?

Correct Answer: C

Q12.In plant cells, how does cytokinesis differ from that in animal cells?

Correct Answer: B

Q13.In which phase of the cell cycle does DNA replication occur?

Correct Answer: B

Q14.What is the primary function of meiosis in sexually reproducing organisms?

Correct Answer: C

Q15.Which structure forms during cytokinesis in plant cells?

Correct Answer: B

Q16.During which phase of mitosis do the chromosomes become most easily visible under a microscope?

Correct Answer: B

Q17.In plant cells, what structure is responsible for the formation of the new cell wall during cytokinesis?

Correct Answer: A

Q18.Which phase of the cell cycle is characterized by DNA replication?

Correct Answer: B

Q19.Which of the following is a key event during prophase I of meiosis?

Correct Answer: B

Q20.During which phase of meiosis does the crossing over of genetic material between homologous chromosomes occur?

Correct Answer: A

Q21.What marks the beginning of anaphase during mitosis?

Correct Answer: C

Q22.Which of the following events occurs during anaphase of mitosis?

Correct Answer: C

Q23.Which phase of meiosis is characterized by the pairing of homologous chromosomes and the formation of the synaptonemal complex?

Correct Answer: B

Q24.During which phase of mitosis do the chromatids separate and move to opposite poles?

Correct Answer: C

Q25.Which of the following statements best describes the significance of mitosis in multicellular organisms?

Correct Answer: C

Q26.What marks the beginning of telophase during mitosis?

Correct Answer: C

Q27.During which stage of mitosis does the nuclear envelope reappear and the nucleolus become visible again?

Correct Answer: D

Q28.Which of the following events characterizes the anaphase stage of mitosis?

Correct Answer: C

Q29.What is the primary function of cytokinesis in cell division?

Correct Answer: C

Q30.During which stage of mitosis do the chromosomes align at the equatorial plate and attach to spindle fibers via kinetochores?

Correct Answer: B

Q31.Which of the following processes occurs during cytokinesis in plant cells?