Cell Cycle and Cell Division - Question Paper

Section A: Multiple Choice Questions (MCQs) - 100 Questions

Choose the correct answer from the given options.

The cell cycle is an ordered series of events that leads to: a) Cell death b) Cell division and DNA duplication c) Protein synthesis only d) RNA formation
Which phase of the cell cycle is the longest? a) G1 phase b) S phase c) Interphase d) M phase
During which phase does DNA replication occur? a) G1 phase b) S phase c) G2 phase d) M phase
What happens during G1 phase? a) DNA replication b) Cell grows and synthesizes proteins c) Cell division d) Nuclear envelope breaks down
The G2 phase is characterized by: a) DNA replication b) Cell growth and protein production for division c) Chromosome condensation d) Spindle fiber formation
Mitosis results in how many daughter cells? a) One b) Two c) Three d) Four
The daughter cells produced by mitosis are: a) Genetically different b) Genetically identical c) Haploid d) Polyploid
During which stage of mitosis do chromosomes become visible? a) Prophase b) Metaphase c) Anaphase d) Telophase
The metaphase plate is located at: a) The poles of the cell b) The nuclear envelope c) The equator of the cell d) The cytoplasm
Sister chromatids separate during: a) Prophase b) Metaphase c) Anaphase d) Telophase
The nuclear envelope re-forms during: a) Prophase b) Metaphase c) Anaphase d) Telophase
Cytokinesis refers to: a) Nuclear division b) Chromosome condensation c) Division of cytoplasm d) DNA replication
Meiosis reduces chromosome number by: a) One-fourth b) Half c) Three-fourths d) Double
Meiosis produces how many cells? a) Two b) Three c) Four d) Eight
The cells produced by meiosis are: a) Diploid b) Haploid c) Triploid d) Tetraploid
Homologous chromosomes are: a) Identical chromosomes b) Chromosomes with same genes from both parents c) Sister chromatids d) Unpaired chromosomes
Crossing over occurs during: a) Mitosis b) Prophase I of meiosis c) Metaphase II of meiosis d) Interphase
Crossing over results in: a) Cell death b) Genetic recombination c) DNA damage d) Chromosome loss
Which process is responsible for growth and repair? a) Meiosis b) Mitosis c) Crossing over d) Fertilization
Sexual reproduction involves: a) Mitosis only b) Meiosis only c) Both mitosis and meiosis d) Neither mitosis nor meiosis
Spindle fibers begin to form during: a) Interphase b) Prophase c) Metaphase d) Telophase
The process of chromosome condensation occurs in: a) G1 phase b) S phase c) G2 phase d) Prophase
How many divisions occur in mitosis? a) One b) Two c) Three d) Four
How many divisions occur in meiosis? a) One b) Two c) Three d) Four
Asexual reproduction involves: a) Mitosis b) Meiosis c) Fertilization d) Crossing over
The chromosome number remains the same in: a) Mitosis b) Meiosis c) Both d) Neither
Genetic variation is produced in: a) Mitosis only b) Meiosis only c) Both mitosis and meiosis d) Neither
The equatorial plate is formed during: a) Prophase b) Metaphase c) Anaphase d) Telophase
Sister chromatids are held together by: a) Spindle fibers b) Centromeres c) Nuclear envelope d) Cytoplasm
The longest phase of mitosis is: a) Prophase b) Metaphase c) Anaphase d) Telophase
DNA synthesis occurs during which phase? a) G1 b) S c) G2 d) M
The cell checkpoint that ensures DNA has been replicated occurs at: a) G1/S boundary b) S/G2 boundary c) G2/M boundary d) M/G1 boundary
Centrioles duplicate during: a) G1 phase b) S phase c) G2 phase d) M phase
The shortest phase of mitosis is: a) Prophase b) Metaphase c) Anaphase d) Telophase
Chromosomes are most condensed during: a) Prophase b) Metaphase c) Anaphase d) Telophase
The mitotic spindle is fully formed during: a) Prophase b) Metaphase c) Anaphase d) Telophase
Chromosome movement to poles occurs during: a) Prophase b) Metaphase c) Anaphase d) Telophase
Nuclear envelope breakdown occurs during: a) Prophase b) Metaphase c) Anaphase d) Telophase
The first phase of meiosis is: a) Prophase I b) Metaphase I c) Anaphase I d) Telophase I
Independent assortment occurs during: a) Prophase I b) Metaphase I c) Anaphase I d) Telophase I
Homologous chromosomes separate during: a) Anaphase I b) Anaphase II c) Metaphase I d) Metaphase II
Sister chromatids separate during meiosis in: a) Anaphase I b) Anaphase II c) Metaphase I d) Metaphase II
The reduction division in meiosis occurs during: a) Meiosis I b) Meiosis II c) Both divisions d) Neither division
Synapsis occurs during: a) Prophase I b) Metaphase I c) Prophase II d) Metaphase II
Bivalents are formed during: a) Mitosis b) Meiosis I c) Meiosis II d) Interphase
The number of chromatids in a bivalent is: a) Two b) Three c) Four d) Eight
Chiasmata are points where: a) Spindle fibers attach b) Crossing over occurs c) Chromosomes break d) Centromeres divide
Gametes are produced by: a) Mitosis b) Meiosis c) Binary fission d) Budding
The diploid number in humans is: a) 23 b) 46 c) 48 d) 44
The haploid number in humans is: a) 23 b) 46 c) 48 d) 44
Somatic cells undergo: a) Mitosis b) Meiosis c) Both d) Neither
Germ cells undergo: a) Mitosis only b) Meiosis only c) Both mitosis and meiosis d) Neither
The cell cycle checkpoint that prevents damaged DNA from being passed to daughter cells occurs at: a) G1/S b) Intra-S c) G2/M d) All of the above
Cyclin proteins regulate: a) DNA replication b) Cell cycle progression c) Chromosome condensation d) Spindle formation
The point of no return in the cell cycle is: a) Start point b) Restriction point c) G2/M checkpoint d) Spindle checkpoint
Apoptosis is: a) Cell division b) Cell growth c) Programmed cell death d) DNA repair
Cancer is characterized by: a) Controlled cell division b) Uncontrolled cell division c) No cell division d) Slow cell division
Tumor suppressor genes: a) Promote cell division b) Inhibit cell division c) Have no effect on cell division d) Only work in cancer cells
Oncogenes: a) Prevent cancer b) Promote cancer c) Have no relation to cancer d) Only exist in normal cells
The G0 phase is: a) Part of mitosis b) A resting phase c) DNA replication phase d) Cell division phase
Cells that never divide are in: a) G1 phase b) S phase c) G2 phase d) G0 phase
The spindle checkpoint ensures: a) DNA replication is complete b) All chromosomes are attached to spindle c) Cell size is adequate d) Nutrients are sufficient
Polyploidy results from errors in: a) DNA replication b) Chromosome separation c) Protein synthesis d) Cell metabolism
Nondisjunction can occur during: a) Mitosis only b) Meiosis only c) Both mitosis and meiosis d) Neither process
Down syndrome results from: a) Missing chromosome b) Extra chromosome 21 c) Broken chromosome d) Inverted chromosome
Klinefelter syndrome has the karyotype: a) 45,X b) 47,XXY c) 47,XYY d) 46,XX
Turner syndrome has the karyotype: a) 45,X b) 47,XXY c) 47,XYY d) 46,XY
Meiotic arrest occurs in: a) Male gametes only b) Female gametes only c) Both male and female gametes d) Neither male nor female gametes
Oogenesis involves: a) Mitosis only b) Meiosis only c) Both mitosis and meiosis d) Neither process
Spermatogenesis involves: a) Mitosis only b) Meiosis only c) Both mitosis and meiosis d) Neither process
The primary oocyte is arrested in: a) Prophase I b) Metaphase I c) Prophase II d) Metaphase II
The secondary oocyte is arrested in: a) Prophase I b) Metaphase I c) Prophase II d) Metaphase II
Fertilization triggers completion of: a) Meiosis I b) Meiosis II c) Mitosis d) DNA replication
The first polar body is produced after: a) Meiosis I b) Meiosis II c) Fertilization d) Mitosis
How many functional gametes are produced from one primary spermatocyte? a) One b) Two c) Three d) Four
How many functional gametes are produced from one primary oocyte? a) One b) Two c) Three d) Four
Polar bodies eventually: a) Become eggs b) Become sperm c) Degenerate d) Divide further
The acrosome reaction occurs in: a) Eggs b) Sperm c) Somatic cells d) Polar bodies
Capacitation occurs in: a) Eggs b) Sperm c) Somatic cells d) Polar bodies
The cortical reaction prevents: a) Fertilization b) Polyspermy c) Implantation d) Development
Parthenogenesis is: a) Sexual reproduction b) Asexual reproduction c) Fertilization d) Meiosis
Alternation of generations involves: a) Only diploid phases b) Only haploid phases c) Both diploid and haploid phases d) Neither phase
In plants, the sporophyte is: a) Haploid b) Diploid c) Triploid d) Polyploid
In plants, the gametophyte is: a) Haploid b) Diploid c) Triploid d) Polyploid
Spores are produced by: a) Mitosis b) Meiosis c) Fertilization d) Budding
Gametes are produced by: a) Mitosis b) Meiosis c) Both processes d) Neither process
Double fertilization occurs in: a) Animals b) Fungi c) Flowering plants d) Bacteria
The endosperm is: a) Diploid b) Triploid c) Haploid d) Tetraploid
Vegetative reproduction involves: a) Mitosis b) Meiosis c) Fertilization d) Spore formation
Binary fission occurs in: a) Animals b) Plants c) Bacteria d) Fungi
Budding is a form of: a) Sexual reproduction b) Asexual reproduction c) Meiosis d) Fertilization
Fragmentation and regeneration occur in: a) Simple organisms b) Complex organisms c) Only plants d) Only animals
Clone formation involves: a) Sexual reproduction b) Asexual reproduction c) Meiosis d) Fertilization
Identical twins result from: a) Two eggs fertilized separately b) One embryo splitting c) Nondisjunction d) Polyploidy
Fraternal twins result from: a) Two eggs fertilized separately b) One embryo splitting c) Nondisjunction d) Polyploidy
Stem cells are characterized by: a) Inability to divide b) Ability to differentiate c) Short lifespan d) Specific function
Totipotent cells can: a) Form any cell type b) Form limited cell types c) Not divide d) Only form gametes
Pluripotent cells can: a) Form any cell type including extraembryonic b) Form most cell types but not extraembryonic c) Form only one cell type d) Not differentiate
Cell differentiation involves: a) Changes in DNA sequence b) Changes in gene expression c) Loss of chromosomes d) Gain of chromosomes
Senescence refers to: a) Cell division b) Cell aging c) Cell death d) Cell growth

Section B: One Mark Questions - 100 Questions

Answer in one word or one sentence.

Name the longest phase of the cell cycle.
What does S phase stand for?
During which phase does DNA replication occur?
Name the process of cytoplasm division.
How many daughter cells are produced by mitosis?
How many daughter cells are produced by meiosis?
What type of cells does mitosis produce - haploid or diploid?
What type of cells does meiosis produce - haploid or diploid?
In which phase do chromosomes become visible?
Where do chromosomes align during metaphase?
When do sister chromatids separate in mitosis?
When does the nuclear envelope reform?
What are homologous chromosomes?
Define crossing over.
In which phase of meiosis does crossing over occur?
What is the result of crossing over?
Name the process responsible for growth and repair.
Name the process involved in sexual reproduction.
How many divisions occur in mitosis?
How many divisions occur in meiosis?
What is cytokinesis?
What is a bivalent?
What are chiasmata?
What is synapsis?
Define gametes.
What is the diploid chromosome number in humans?
What is the haploid chromosome number in humans?
What type of division do somatic cells undergo?
What type of division do germ cells undergo?
What is apoptosis?
What is the G0 phase?
What are cyclins?
What is nondisjunction?
What causes Down syndrome?
What is the karyotype for Turner syndrome?
What is the karyotype for Klinefelter syndrome?
What is oogenesis?
What is spermatogenesis?
Where is the primary oocyte arrested?
Where is the secondary oocyte arrested?
What triggers completion of meiosis II in the egg?
How many functional sperm are produced from one primary spermatocyte?
How many functional eggs are produced from one primary oocyte?
What happens to polar bodies?
What is parthenogenesis?
What is alternation of generations?
What is the ploidy of sporophyte in plants?
What is the ploidy of gametophyte in plants?
How are spores produced?
What is double fertilization?
What is the ploidy of endosperm?
What type of reproduction is budding?
What is binary fission?
What are clones?
How do identical twins form?
How do fraternal twins form?
What are stem cells?
What are totipotent cells?
What are pluripotent cells?
What is cell differentiation?
What is senescence?
What is the metaphase plate?
What holds sister chromatids together?
What is the spindle checkpoint?
What are oncogenes?
What are tumor suppressor genes?
What is cancer?
What is polyploidy?
What is the restriction point?
What is the acrosome reaction?
What is capacitation?
What is the cortical reaction?
What prevents polyspermy?
What is vegetative reproduction?
What is fragmentation?
What is regeneration?
What is clone formation?
What is meiotic arrest?
What are centrioles?
When do centrioles duplicate?
What is the equatorial plate?
What is independent assortment?
What is reduction division?
What is the first polar body?
What is the second polar body?
What is fertilization?
What is implantation?
What is development?
What is growth?
What is repair?
What is replacement?
What is reproduction?
What is inheritance?
What is variation?
What is recombination?
What is segregation?
What is assortment?
What is linkage?
What is mutation?
What is evolution?

Section C: Two Marks Questions - 100 Questions

Answer in 2-3 sentences or provide brief explanations.

Explain the significance of interphase in the cell cycle.
Describe what happens during G1 phase.
Explain the importance of S phase.
Describe the events of G2 phase.
Compare the duration of interphase with mitotic phase.
Explain why interphase is crucial for successful cell division.
Describe the events of prophase in mitosis.
Explain what happens during metaphase.
Describe the process of anaphase.
Explain the events of telophase.
Compare prophase and telophase.
Explain the relationship between mitosis and cytokinesis.
Describe the significance of mitosis in growth.
Explain how mitosis contributes to repair.
Describe the role of mitosis in asexual reproduction.
Compare mitosis in plant and animal cells.
Explain the formation of the mitotic spindle.
Describe the role of centromeres in mitosis.
Explain chromosome condensation during mitosis.
Describe the importance of chromosome alignment.
Explain the difference between meiosis I and meiosis II.
Describe the significance of homologous chromosomes.
Explain the process of synapsis.
Describe crossing over and its importance.
Explain independent assortment.
Describe the formation of bivalents.
Explain the significance of chiasmata.
Describe reduction division.
Explain genetic recombination in meiosis.
Compare sister chromatids and homologous chromosomes.
Describe the differences between diploid and haploid cells.
Explain the role of meiosis in sexual reproduction.
Compare the outcomes of mitosis and meiosis.
Describe the cellular differences after mitosis and meiosis.
Explain the importance of chromosome number reduction.
Describe how meiosis contributes to genetic variation.
Explain the concept of genetic diversity.
Describe the role of crossing over in evolution.
Explain the significance of independent assortment in inheritance.
Compare the genetic content of parent and daughter cells in both processes.
Describe the cell cycle checkpoints.
Explain the G1/S checkpoint.
Describe the spindle checkpoint.
Explain the role of cyclins in cell cycle control.
Describe what happens when checkpoints fail.
Explain the relationship between cell cycle and cancer.
Describe apoptosis and its importance.
Explain the difference between apoptosis and necrosis.
Describe the G0 phase and its significance.
Explain why some cells never divide.
Describe nondisjunction and its consequences.
Explain how chromosomal disorders arise.
Describe Down syndrome and its cause.
Explain Turner syndrome.
Describe Klinefelter syndrome.
Explain the effects of aneuploidy.
Describe polyploidy and its occurrence.
Explain the difference between monosomy and trisomy.
Describe how nondisjunction can occur in meiosis.
Explain the consequences of nondisjunction in mitosis.
Describe gametogenesis in males.
Explain oogenesis in females.
Compare spermatogenesis and oogenesis.
Describe the formation of polar bodies.
Explain meiotic arrest in female gametes.
Describe the timing of meiosis in male and female gametes.
Explain the difference in gamete production between males and females.
Describe the role of hormones in gametogenesis.
Explain the significance of unequal division in oogenesis.
Describe the fate of polar bodies.
Explain fertilization as a cellular process.
Describe the restoration of diploid number after fertilization.
Explain the role of meiosis in life cycles.
Describe alternation of generations.
Explain the diploid and haploid phases in plant life cycles.
Describe sporogenesis in plants.
Explain the formation of male and female gametes in plants.
Describe double fertilization in flowering plants.
Explain the significance of endosperm formation.
Compare sexual and asexual reproduction at the cellular level.
Describe vegetative reproduction.
Explain binary fission in prokaryotes.
Describe budding as a form of reproduction.
Explain fragmentation and regeneration.
Describe the advantages and disadvantages of asexual reproduction.
Explain the advantages and disadvantages of sexual reproduction.
Describe the formation of identical twins.
Explain the formation of fraternal twins.
Describe stem cells and their properties.
Explain the difference between totipotent and pluripotent cells.
Describe cell differentiation.
Explain the role of gene expression in cell differentiation.
Describe cellular senescence.
Explain the relationship between aging and cell division.
Describe the Hayflick limit.
Explain telomeres and their role in aging.
Describe cancer as a disease of cell division.
Explain oncogenes and tumor suppressor genes.
Describe metastasis at the cellular level.
Explain the importance of understanding cell division for medicine.

Section D: Three Marks Questions - 50 Questions

Provide detailed explanations with examples where appropriate.

Describe the complete cell cycle with its phases and explain the importance of each phase in preparing the cell for division.
Explain the detailed process of mitosis, describing each stage and its significance in maintaining chromosome number.
Compare and contrast mitosis and meiosis, highlighting their differences in terms of purpose, process, and outcomes.
Describe the process of meiosis in detail, explaining how it leads to genetic variation and the formation of gametes.
Explain the significance of crossing over in meiosis and how it contributes to genetic diversity and evolution.
Describe the cell cycle checkpoints and explain how they prevent errors in cell division and their role in preventing cancer.
Explain the process of gametogenesis in both males and females, highlighting the differences and similarities.
Describe chromosomal disorders that result from errors in meiosis, explaining their causes and consequences with examples.
Explain the concept of alternation of generations in plants and describe how it relates to cell division processes.
Describe the role of cell division in growth, repair, and reproduction, providing specific examples for each.
Explain how cancer develops as a result of uncontrolled cell division and describe the molecular basis of cancer.
Describe the importance of cell cycle regulation and explain what happens when this regulation breaks down.
Explain the process of fertilization and describe how it restores the diploid chromosome number and initiates development.
Describe stem cells, their types, and their role in development and medical applications.
Explain the relationship between cell division and aging, describing the mechanisms that limit cell division.
Describe the differences between sexual and asexual reproduction at the cellular level and explain their evolutionary significance.
Explain the molecular mechanisms that control cell division, including the role of cyclins and checkpoints.
Describe how environmental factors can affect cell division and lead to mutations or cancer.
Explain the importance of DNA repair mechanisms and how they relate to cell division and cancer prevention.
Describe the process of apoptosis and explain its importance in development and disease prevention.
Explain how chromosomes are organized and behave during cell division, including the role of the spindle apparatus.
Describe the differences in cell division between prokaryotes and eukaryotes.
Explain the concept of ploidy and describe how changes in chromosome number affect organisms.
Describe the role of cell division in immune system function and explain how immune cells reproduce.
Explain how plant cell division differs from animal cell division and describe the unique features of plant cell division.
Describe the relationship between cell size and cell division, explaining the factors that trigger cell division.
Explain the process of regeneration in organisms and describe the role of cell division in this process.
Describe how hormones regulate cell division and provide examples from both plants and animals.
Explain the concept of cell senescence and describe its role in aging and cancer prevention.
Describe the evolutionary significance of sexual reproduction and explain how meiosis contributes to evolutionary success.
Explain how errors in cell division can lead to genetic disorders and describe methods to detect these disorders.
Describe the role of cell division in wound healing and tissue repair, explaining the different phases involved.
Explain the concept of totipotency and pluripotency, describing their importance in development and regenerative medicine.
Describe how cell division is regulated during development and explain the concept of developmental checkpoints.
Explain the relationship between nutrition and cell division, describing how nutrient availability affects cell cycle progression.
Describe the role of oxygen in cell division and explain how hypoxia affects cell cycle progression.
Explain how radiation and chemicals can affect cell division and describe the mechanisms of mutagenesis.
Describe the process of tissue formation through cell division and differentiation during embryonic development.
Explain the concept of contact inhibition and describe its role in controlling cell division in tissues.
Describe how viruses can affect cell division and explain the relationship between viral infections and cancer.
Explain the role of telomeres in cell division and describe how telomerase activity affects cellular lifespan.
Describe the process of meiotic drive and explain how it can affect inheritance patterns.
Explain the concept of hybrid vigor and describe how it relates to genetic variation produced by sexual reproduction.
Describe the role of cell division in plant growth and development, including the function of meristematic tissues.
Explain how cell division contributes to homeostasis in multicellular organisms.
Describe the differences between normal cell division and cancer cell division, explaining the loss of growth control.
Explain the role of cell division in the life cycles of different organisms, providing examples from various kingdoms.
Describe how cell division patterns contribute to the formation of different tissue types and organ systems.
Explain the relationship between cell division and metabolism, describing how energy requirements change during the cell cycle.
Describe the future prospects of cell division research and its potential applications in medicine and biotechnology.

Answer Key Guidelines

Cell Cycle and Cell Division - Answer Script

Section A: Multiple Choice Questions (MCQs)

b) Cell division and DNA duplication
c) Interphase
b) S phase
b) Cell grows and synthesizes proteins
b) Cell growth and protein production for division
b) Two
b) Genetically identical
a) Prophase
c) The equator of the cell
c) Anaphase
d) Telophase
c) Division of cytoplasm
b) Half
c) Four
b) Haploid
b) Chromosomes with same genes from both parents
b) Prophase I of meiosis
b) Genetic recombination
b) Mitosis
c) Both mitosis and meiosis
b) Prophase
d) Prophase
a) One
b) Two
a) Mitosis
a) Mitosis
b) Meiosis only
b) Metaphase
b) Centromeres
a) Prophase
b) S
c) G2/M boundary
b) S phase
c) Anaphase
b) Metaphase
b) Metaphase
c) Anaphase
a) Prophase
a) Prophase I
b) Metaphase I
a) Anaphase I
b) Anaphase II
a) Meiosis I
a) Prophase I
b) Meiosis I
c) Four
b) Crossing over occurs
b) Meiosis
b) 46
a) 23
a) Mitosis
c) Both mitosis and meiosis
d) All of the above
b) Cell cycle progression
b) Restriction point
c) Programmed cell death
b) Uncontrolled cell division
b) Inhibit cell division
b) Promote cancer
b) A resting phase
d) G0 phase
b) All chromosomes are attached to spindle
b) Chromosome separation
c) Both mitosis and meiosis
b) Extra chromosome 21
b) 47,XXY
a) 45,X
b) Female gametes only
c) Both mitosis and meiosis
c) Both mitosis and meiosis
a) Prophase I
d) Metaphase II
b) Meiosis II
a) Meiosis I
d) Four
a) One
c) Degenerate
b) Sperm
b) Sperm
b) Polyspermy
b) Asexual reproduction
c) Both diploid and haploid phases
b) Diploid
a) Haploid
b) Meiosis
a) Mitosis
c) Flowering plants
b) Triploid
a) Mitosis
c) Bacteria
b) Asexual reproduction
a) Simple organisms
b) Asexual reproduction
b) One embryo splitting
a) Two eggs fertilized separately
b) Ability to differentiate
a) Form any cell type
b) Form most cell types but not extraembryonic
b) Changes in gene expression
b) Cell aging

Section B: One Mark Questions

Interphase
Synthesis
S phase
Cytokinesis
Two
Four
Diploid
Haploid
Prophase
At the metaphase plate.
Anaphase
Telophase
Pairs of chromosomes with the same genes, one from each parent.
The exchange of genetic material between homologous chromosomes.
Prophase I
Genetic recombination
Mitosis
Meiosis
One
Two
The division of the cytoplasm.
A pair of homologous chromosomes.
The points where crossing over has occurred.
The pairing of homologous chromosomes.
Haploid reproductive cells.
46
23
Mitosis
Meiosis
Programmed cell death.
A resting phase where the cell is not dividing.
Proteins that regulate the cell cycle.
The failure of chromosomes to separate properly during cell division.
An extra copy of chromosome 21.
45,X
47,XXY
The process of forming female gametes.
The process of forming male gametes.
Prophase I
Metaphase II
Fertilization
Four
One
They degenerate.
A form of asexual reproduction where an embryo develops without fertilization.
A life cycle that alternates between diploid and haploid generations.
Diploid
Haploid
By meiosis.
A process in flowering plants where two fertilization events occur.
Triploid
Asexual
A method of asexual reproduction in prokaryotes.
Genetically identical individuals.
From the splitting of a single fertilized egg.
From two separate eggs fertilized by two different sperm.
Undifferentiated cells that can develop into various cell types.
Stem cells that can differentiate into any type of cell.
Stem cells that can differentiate into most, but not all, cell types.
The process by which a cell changes to a more specialized type.
The process of aging in a cell.
The plane in the center of the cell where chromosomes align during metaphase.
The centromere.
A checkpoint that ensures all chromosomes are attached to the spindle fibers.
Genes that can transform a cell into a tumor cell.
Genes that protect a cell from one step on the path to cancer.
A disease characterized by uncontrolled cell division.
The state of a cell or organism having more than two paired sets of chromosomes.
A point in G1 phase of the cell cycle where the cell is committed to division.
A reaction that occurs in the acrosome of the sperm as it approaches the egg.
The final step in the maturation of mammalian spermatozoa.
A process initiated during fertilization that prevents polyspermy.
The cortical reaction.
A type of asexual reproduction in plants.
A form of asexual reproduction where an organism is split into fragments.
The process of renewal, restoration, and growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage.
The creation of an organism that is an exact genetic copy of another.
A state where an oocyte is paused in a particular phase of meiosis.
Organelles that serve as the main microtubule organizing centers for animal cells.
S phase
The plane at the equator of the spindle where chromosomes are aligned during metaphase.
The principle that states that different genes independently separate from one another when reproductive cells develop.
The first meiotic division, which reduces the chromosome number by half.
The smaller cell formed during oogenesis that does not develop into an ovum.
The second smaller cell formed during oogenesis that does not develop into an ovum.
The fusion of gametes to initiate the development of a new individual organism.
The attachment of the fertilized egg to the uterine wall.
The process by which an organism grows and changes over time.
The increase in the size of an organism.
The process of replacing or restoring damaged tissue.
The process of replacing old or dead cells.
The production of new organisms.
The passing of traits from parents to offspring.
The differences between individuals in a population.
The process of forming new combinations of alleles.
The separation of alleles during gamete formation.
The independent segregation of genes during the formation of gametes.
The tendency of genes that are located close to each other on a chromosome to be inherited together.
A change in the DNA sequence.
The change in the characteristics of a species over several generations.

Section C: Two Marks Questions

Interphase is the preparatory phase for cell division. It allows the cell to grow, replicate its DNA, and synthesize proteins necessary for mitosis or meiosis.
During the G1 phase, the cell grows in size and synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis.
The S phase is critical because it is when the cell synthesizes a complete copy of the DNA in its nucleus.
In the G2 phase, the cell continues to grow and produces the proteins and organelles required for cell division.
Interphase is significantly longer than the mitotic phase, as it involves detailed preparatory work for cell division.
Interphase is crucial because it ensures that the cell is large enough and has duplicated its DNA and other components to produce two viable daughter cells.
In prophase, chromatin condenses into visible chromosomes, the nuclear envelope breaks down, and the mitotic spindle begins to form.
During metaphase, the chromosomes, attached to the mitotic spindle, align at the metaphase plate in the center of the cell.
In anaphase, the sister chromatids of each chromosome are pulled apart by the spindle fibers and move to opposite poles of the cell.
In telophase, the chromosomes arrive at the poles, decondense, and are enclosed in new nuclear envelopes.
Prophase involves the condensation of chromosomes and breakdown of the nuclear envelope, while telophase is the reverse process.
Mitosis is the division of the nucleus, which is usually followed by cytokinesis, the division of the cytoplasm, to complete cell division.
Mitosis allows for the increase in cell number, which is the basis of growth in multicellular organisms.
Mitosis produces new cells to replace old, damaged, or dead cells, thus repairing tissues.
In asexual reproduction, mitosis allows an organism to produce genetically identical offspring.
In plant cells, a cell plate forms during cytokinesis, while in animal cells, a cleavage furrow is formed.
The mitotic spindle is formed from microtubules that extend from the centrosomes.
Centromeres are the regions where sister chromatids are held together and where spindle fibers attach.
Chromosome condensation makes the long DNA molecules more compact and manageable during cell division.
The alignment of chromosomes at the metaphase plate ensures that each daughter cell receives a complete set of chromosomes.
Meiosis I separates homologous chromosomes, while Meiosis II separates sister chromatids.
Homologous chromosomes carry the same genes and allow for the exchange of genetic material during meiosis.
Synapsis is the pairing of homologous chromosomes during prophase I of meiosis.
Crossing over is the exchange of genetic material between homologous chromosomes, which creates new gene combinations.
Independent assortment is the random orientation of homologous chromosome pairs at the metaphase plate during meiosis I.
Bivalents are pairs of homologous chromosomes that form during prophase I of meiosis.
Chiasmata are the points of contact between homologous chromosomes where crossing over occurs.
Reduction division is the first meiotic division, where the chromosome number is halved.
Genetic recombination in meiosis results from crossing over and independent assortment, creating genetic diversity.
Sister chromatids are identical copies of a chromosome, while homologous chromosomes are pairs of chromosomes with the same genes but potentially different alleles.
Diploid cells have two sets of chromosomes, while haploid cells have one set.
Meiosis produces haploid gametes, which are essential for sexual reproduction.
Mitosis produces two identical diploid cells, while meiosis produces four unique haploid cells.
Cells after mitosis are genetically identical to the parent cell, whereas cells after meiosis are genetically different.
The reduction of chromosome number in meiosis is essential to maintain the correct chromosome number in the offspring after fertilization.
Meiosis contributes to genetic variation through crossing over and independent assortment.
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species.
Crossing over creates new combinations of genes, which can be acted upon by natural selection, driving evolution.
Independent assortment leads to various combinations of parental chromosomes in the gametes, contributing to genetic variation in the offspring.
In mitosis, daughter cells are genetically identical to the parent cell. In meiosis, daughter cells are genetically different from the parent cell and from each other.
Cell cycle checkpoints are control mechanisms that ensure the proper progression of the cell cycle.
The G1/S checkpoint, also known as the restriction point, determines if the cell should commit to division.
The spindle checkpoint ensures that all chromosomes are properly attached to the spindle before anaphase begins.
Cyclins are proteins that regulate the timing of the cell cycle by activating cyclin-dependent kinases.
Failure of checkpoints can lead to errors in cell division, such as aneuploidy, and can contribute to the development of cancer.
Cancer is a disease of uncontrolled cell division, often caused by mutations in genes that regulate the cell cycle.
Apoptosis is programmed cell death, a process that eliminates unwanted or damaged cells.
Apoptosis is a controlled, programmed process, while necrosis is cell death due to injury or disease.
The G0 phase is a non-dividing state that cells can enter from G1.
Some specialized cells, like neurons, enter a permanent G0 phase and do not divide.
Nondisjunction is the failure of chromosomes to separate properly during meiosis, leading to aneuploidy.
Chromosomal disorders arise from changes in the number or structure of chromosomes.
Down syndrome is caused by the presence of an extra copy of chromosome 21.
Turner syndrome is a chromosomal disorder in which a female is born with only one X chromosome.
Klinefelter syndrome is a chromosomal condition that results when a boy is born with an extra copy of the X chromosome.
Aneuploidy is the presence of an abnormal number of chromosomes in a cell, which can lead to various genetic disorders.
Polyploidy is the condition in which the cells of an organism have more than two paired sets of chromosomes. It is common in plants.
Monosomy is the condition of having a diploid chromosome complement in which one chromosome lacks its homologous partner. Trisomy is a condition in which an extra copy of a chromosome is present in the cell nuclei.
Nondisjunction can occur in meiosis I if homologous chromosomes fail to separate, or in meiosis II if sister chromatids fail to separate.
Nondisjunction in mitosis can lead to mosaicism, where an individual has cells with different numbers of chromosomes.
Gametogenesis in males, or spermatogenesis, is the process by which sperm cells are produced in the testes.
Oogenesis is the process by which female gametes, or ova, are created.
Spermatogenesis produces four viable sperm cells, while oogenesis produces one large ovum and smaller polar bodies.
Polar bodies are small cells that are formed during oogenesis and do not develop into ova.
Meiotic arrest is a pause in the process of meiosis, which occurs in female gametes at prophase I and metaphase II.
In males, meiosis is a continuous process, while in females, it is arrested at two stages.
Males produce a large number of small, motile gametes, while females produce a small number of large, non-motile gametes.
Hormones such as FSH and LH regulate gametogenesis in both males and females.
Unequal division in oogenesis ensures that the ovum receives most of the cytoplasm and nutrients.
Polar bodies typically degenerate and are reabsorbed by the body.
Fertilization is the fusion of a sperm and an egg to form a zygote.
Fertilization restores the diploid number of chromosomes by combining the haploid sets from the two gametes.
Meiosis is a key part of the life cycles of sexually reproducing organisms, as it produces the gametes.
Alternation of generations is a life cycle that includes both a multicellular diploid phase and a multicellular haploid phase.
In plants, the diploid phase is the sporophyte, and the haploid phase is the gametophyte.
Sporogenesis is the production of spores in plants.
In plants, male gametes are produced in the pollen grain, and the female gamete is the egg cell in the ovule.
Double fertilization is a complex fertilization mechanism of flowering plants.
Endosperm formation provides nourishment for the developing embryo in the seed.
Sexual reproduction involves the fusion of gametes, leading to genetic variation, while asexual reproduction produces genetically identical offspring.
Vegetative reproduction is a type of asexual reproduction in plants where new plants grow from parts of the parent plant.
Binary fission is a method of asexual reproduction where a cell divides into two identical daughter cells.
Budding is a form of asexual reproduction in which a new individual develops from some generative anatomical point of the parent organism.
Fragmentation is a form of asexual reproduction where an organism is split into fragments, each of which develops into a new organism. Regeneration is the process of renewal, restoration, and growth.
Asexual reproduction is advantageous in stable environments, while its disadvantage is the lack of genetic variation.
Sexual reproduction is advantageous in changing environments due to the genetic variation it produces, but it is more complex and energy-intensive.
Identical twins are formed when a single fertilized egg splits into two.
Fraternal twins are formed when two separate eggs are fertilized by two different sperm.
Stem cells are undifferentiated cells that have the ability to differentiate into various cell types.
Totipotent cells can differentiate into any cell type, including extraembryonic tissues, while pluripotent cells can differentiate into most, but not all, cell types.
Cell differentiation is the process by which a less specialized cell becomes a more specialized cell type.
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product, and it plays a key role in cell differentiation.
Cellular senescence is a state of irreversible cell cycle arrest.
Aging is associated with a decline in the ability of cells to divide.
The Hayflick limit is the number of times a normal human cell population will divide before cell division stops.
Telomeres are protective caps at the ends of chromosomes that shorten with each cell division, contributing to aging.
Cancer is a disease characterized by the uncontrolled division of abnormal cells.
Oncogenes are genes that have the potential to cause cancer, while tumor suppressor genes are genes that protect a cell from one step on the path to cancer.
Metastasis is the spread of cancer cells from the place where they first formed to another part of the body.
Understanding cell division is crucial for medicine as it is fundamental to growth, development, and diseases like cancer.

Section D: Three Marks Questions

The cell cycle consists of Interphase (G1, S, G2) and the M phase (Mitosis/Meiosis and Cytokinesis). G1 is for growth and protein synthesis. S phase is for DNA replication. G2 is for further growth and preparation for division. The M phase is where the cell divides. Each phase is crucial for ensuring that the cell is ready for division and that the daughter cells are viable.
Mitosis is a process of cell division that results in two genetically identical daughter cells. It has four stages: Prophase (chromosomes condense), Metaphase (chromosomes align at the center), Anaphase (sister chromatids separate), and Telophase (new nuclei form). It is essential for growth, repair, and asexual reproduction.
Mitosis and meiosis are both forms of cell division. Mitosis produces two identical diploid cells and is involved in growth and repair. Meiosis produces four unique haploid cells and is involved in sexual reproduction. Meiosis has two rounds of division and involves crossing over, which creates genetic variation.
Meiosis is a two-stage process of cell division. Meiosis I separates homologous chromosomes, and Meiosis II separates sister chromatids. It leads to the formation of four haploid cells, each with a unique combination of genes due to crossing over and independent assortment.
Crossing over occurs during Prophase I of meiosis, where homologous chromosomes exchange genetic material. This creates new combinations of alleles on the chromosomes, which is a major source of genetic diversity and provides the raw material for evolution by natural selection.
Cell cycle checkpoints are control points that monitor the progression of the cell cycle. The main checkpoints are the G1/S checkpoint, the G2/M checkpoint, and the spindle checkpoint. They prevent errors in DNA replication and chromosome segregation, and their failure can lead to mutations and cancer.
Gametogenesis is the process of forming gametes. In males, spermatogenesis produces four sperm cells from a primary spermatocyte. In females, oogenesis produces one large egg cell and polar bodies from a primary oocyte. Spermatogenesis is a continuous process, while oogenesis is arrested at certain stages.
Chromosomal disorders can result from errors in meiosis, such as nondisjunction. This can lead to conditions like Down syndrome (Trisomy 21), Turner syndrome (XO), and Klinefelter syndrome (XXY). These conditions are caused by an abnormal number of chromosomes and have various physical and developmental consequences.
Alternation of generations is a life cycle found in plants and some algae, where there is an alternation between a multicellular diploid sporophyte and a multicellular haploid gametophyte. The sporophyte produces spores by meiosis, and the gametophyte produces gametes by mitosis.
Cell division is fundamental to life. It allows for the growth of multicellular organisms from a single cell. It is also essential for repairing damaged tissues and replacing old cells. In many organisms, it is the basis of reproduction, both asexual and sexual.
Cancer develops when cells lose control over their division and proliferate uncontrollably. This is often due to mutations in genes that regulate the cell cycle, such as oncogenes and tumor suppressor genes. These mutations can lead to the formation of tumors and the spread of cancer to other parts of the body.
The regulation of the cell cycle is crucial for normal growth and development. When this regulation breaks down, it can lead to uncontrolled cell division and the development of diseases like cancer.
Fertilization is the fusion of a male and a female gamete to form a zygote. This process restores the diploid chromosome number and triggers the development of a new individual.
Stem cells are undifferentiated cells that can differentiate into specialized cells and can divide to produce more stem cells. There are different types of stem cells, such as totipotent, pluripotent, and multipotent stem cells. They have great potential in medicine for repairing damaged tissues and treating diseases.
The process of aging is linked to cell division. Most cells have a limited number of times they can divide, known as the Hayflick limit. This is related to the shortening of telomeres, which are protective caps on the ends of chromosomes.
Sexual reproduction involves the fusion of gametes from two parents, leading to genetic variation in the offspring. Asexual reproduction involves a single parent and produces genetically identical offspring. Sexual reproduction is advantageous in changing environments, while asexual reproduction is advantageous in stable environments.
Cell division is controlled by a complex network of proteins, including cyclins and cyclin-dependent kinases (CDKs). These proteins regulate the progression through the different phases of the cell cycle and are controlled by various checkpoints.
Environmental factors such as radiation and certain chemicals can damage DNA and interfere with cell division. This can lead to mutations and increase the risk of cancer.
DNA repair mechanisms are essential for maintaining the integrity of the genome. They correct errors that occur during DNA replication and damage caused by environmental factors. These mechanisms are closely linked to cell cycle checkpoints and are crucial for preventing cancer.
Apoptosis is a process of programmed cell death that is essential for normal development and for removing damaged or infected cells. It is a highly regulated process that plays a key role in preventing cancer.
During cell division, chromosomes are condensed and organized by the spindle apparatus, which is made of microtubules. The spindle ensures that the chromosomes are accurately segregated to the daughter cells.
Prokaryotic cells divide by a simple process called binary fission, while eukaryotic cells have a more complex process of cell division involving mitosis or meiosis.
Ploidy refers to the number of sets of chromosomes in a cell. Changes in chromosome number, such as aneuploidy and polyploidy, can have significant effects on an organism's development and health.
Cell division is essential for the function of the immune system. Immune cells, such as lymphocytes, divide rapidly to mount a response against pathogens.
Plant cell division differs from animal cell division in that plant cells form a cell plate during cytokinesis, while animal cells form a cleavage furrow. Plant cells also have a rigid cell wall that must be taken into account during division.
The size of a cell is a key factor that triggers cell division. As a cell grows, its surface area-to-volume ratio decreases, which can make it difficult for the cell to transport nutrients and waste products. This can trigger the cell to divide.
Regeneration is the process by which some organisms can regrow lost or damaged body parts. This process relies on cell division to produce new cells to replace the lost tissue.
Hormones can regulate cell division in both plants and animals. For example, growth hormones can stimulate cell division, while other hormones can inhibit it.
Cell senescence is a state of irreversible cell cycle arrest that can be triggered by various factors, such as telomere shortening and DNA damage. It is thought to play a role in aging and cancer prevention.
Sexual reproduction is evolutionarily significant because it creates genetic variation in a population, which is the raw material for natural selection. Meiosis, with its processes of crossing over and independent assortment, is the key to this variation.
Errors in cell division can lead to genetic disorders such as Down syndrome and Turner syndrome. These disorders can be detected using methods such as karyotyping and genetic testing.
Cell division is essential for wound healing and tissue repair. When a tissue is damaged, cells in the surrounding area divide to produce new cells to replace the damaged ones.
Totipotency and pluripotency are properties of stem cells that describe their ability to differentiate into other cell types. Totipotent cells can differentiate into any cell type, while pluripotent cells can differentiate into most, but not all, cell types. These properties are important for development and regenerative medicine.
Cell division is tightly regulated during development to ensure that tissues and organs are formed correctly. This regulation is controlled by a complex network of genes and signaling pathways.
Nutrition can affect cell division by providing the necessary building blocks and energy for cell growth and replication. A lack of nutrients can cause cells to stop dividing.
Oxygen is essential for aerobic respiration, which provides the energy for cell division. Hypoxia, or a lack of oxygen, can inhibit cell division.
Radiation and chemicals can damage DNA and interfere with cell division. This can lead to mutations and increase the risk of cancer.
During embryonic development, cells divide and differentiate to form the various tissues and organs of the body. This process is controlled by a complex network of genes and signaling pathways.
Contact inhibition is a process that stops cells from dividing when they come into contact with each other. This is an important mechanism for controlling cell growth in tissues.
Some viruses can interfere with cell division and cause cancer. They do this by inserting their own genes into the host cell's DNA, which can disrupt the normal regulation of the cell cycle.
Telomeres are protective caps on the ends of chromosomes that shorten with each cell division. Telomerase is an enzyme that can lengthen telomeres, and its activity is important for cellular lifespan.
Meiotic drive is a process that can cause some alleles to be passed on to the next generation more often than others. This can affect inheritance patterns and have evolutionary consequences.
Hybrid vigor, or heterosis, is the tendency of a crossbred individual to show qualities superior to those of both parents. This is thought to be due to the increased genetic variation that results from sexual reproduction.
Cell division is essential for plant growth and development. Meristematic tissues are regions of actively dividing cells that are responsible for the growth of the plant.
Cell division contributes to homeostasis by replacing old or damaged cells and by allowing for growth and repair.
Normal cell division is a tightly regulated process, while cancer cell division is uncontrolled. Cancer cells have lost the ability to respond to the signals that normally control cell growth.
Cell division plays a key role in the life cycles of all organisms. In some organisms, it is the basis of reproduction, while in others, it is essential for growth and development.
The patterns of cell division during development determine the formation of different tissue types and organ systems.
Cell division is an energy-intensive process that requires a lot of ATP. The metabolism of the cell changes during the cell cycle to meet these energy demands.
Research on cell division has the potential to lead to new treatments for diseases such as cancer and to new applications in biotechnology, such as regenerative medicine.

Cell Cycle and Cell Divisions