75 practice questions on Cell Cycle and Cell Division , sorted Easy → Hard. Try each one first, then open its answer page for the worked explanation. Want the full theory first? Read the Cell Cycle and Cell Division notes .
The Cell Cycle G1 S G2 M (Mitosis) G1+S+G2 = Interphase (the longest part of the cycle, where the cell spends most of its time) The cell cycle: G1 (growth and preparation), S (DNA replication, chromosome number stays 2n but DNA content doubles), G2 (final checks before division), and M (mitosis itself) - together, G1 +S+G2 make up interphase.
Easy - 25 questions Q1.
Meiosis takes place in the ___ cells of an organism:
A Reproductive (germ)B Skin (epidermal)C Muscle (contractile)D Nerve (conducting)Show answer & explanation →
Q2.
In plant cells, cytokinesis is accomplished by the formation of a:
A Cleavage furrowB Cell plateC Contractile ringD CentrioleShow answer & explanation →
Q3.
Meiosis I is called a reductional division because it:
A Copies the DNA a second timeB Keeps the chromosome number the sameC Halves the chromosome numberD Joins two gametes togetherShow answer & explanation →
Q4.
The stage of mitosis best suited for studying the size and shape of chromosomes is:
A AnaphaseB TelophaseC ProphaseD MetaphaseShow answer & explanation →
Q5.
In a multicellular organism, mitosis is mainly responsible for:
A Growth and repair of tissuesB Formation of gametesC Introducing genetic variationD Halving the chromosome numberShow answer & explanation →
Q8.
The purpose of meiosis is:
A Growth and repairB Production of gametes (sex cells)C Replacement of damaged cellsD All cell divisionsShow answer & explanation →
Q9.
DNA replication occurs during which phase of the cell cycle?
A G<sub>1</sub> phase, before DNA synthesis beginsB S phase (Synthesis)C G<sub>2</sub> phase, after DNA synthesis endsD Mitosis, during chromosome separationShow answer & explanation →
Q11.
During anaphase of mitosis:
A Nuclear envelope vesicles disperse into the cytoplasmB Chromosomes coil tightly and condense for divisionC Sister chromatids separate and move to polesD Spindle microtubules polymerize from centrosomesShow answer & explanation →
Q14.
Homologous chromosomes separate during:
A Mitosis anaphaseB Meiosis I anaphaseC Meiosis II anaphaseD Prophase IShow answer & explanation →
Q15.
Cancer is characterized by:
A Controlled and well-regulated cell divisionB Programmed cell death pathways activatingC Uncontrolled cell division (mitosis)D Errors occurring only during meiosisShow answer & explanation →
Q17.
Telophase is characterized by:
A Chromosome condensation into visible threadsB Chromosome alignment at the cell equatorC Reformation of nuclear envelopeD Spindle fiber formation from centrosomesShow answer & explanation →
Q18.
Cytokinesis in animal cells involves:
A Cell plate formationB Cleavage furrowC Cell wall formationD Spindle disappearanceShow answer & explanation →
Q19.
Prophase of mitosis is characterized by:
A Chromosome decondensation into loose chromatinB Nuclear envelope remaining fully intactC Chromosomes condense and become visibleD Chromosomes moving toward the cell equatorShow answer & explanation →
Q20.
What is the ploidy of a cell after meiosis I?
A Tetraploid (4n)B Diploid (2n)C Haploid (n)D Triploid (3n)Show answer & explanation →
Q21.
The spindle apparatus is made of:
A Actin filamentsB MicrotubulesC Intermediate filamentsD Collagen fibersShow answer & explanation →
Q22.
Interphase is:
A The stage of active division mainlyB The phase between divisions (G<sub>1</sub>, S, G<sub>2</sub>)C Mainly the G<sub>1</sub> stageD Mainly DNA synthesisShow answer & explanation →
Q23.
Bivalent is formed during meiosis I when:
A Sister chromatids pairing along their lengthB Homologous chromosomes pair up (synapsis)C Non-homologous chromosomes pairing randomlyD All chromosomes aligning at the spindle equatorShow answer & explanation →
Q24.
Checkpoint controls in the cell cycle ensure:
A Cell division proceeds continuously at the fastest possible rate without pauseB DNA is correctly replicated and chromosomes properly aligned before proceedingC Cell division is permanently and irreversibly halted in every body tissueD Only the G<sub>1</sub> restriction point is monitored, with all later phases uncheckedShow answer & explanation →
Medium - 25 questions Q26.
The prolonged diplotene stage, in which the cell may stay arrested for years, is seen in the meiosis of:
A Human malesB Human femalesC BacteriaD All flowering plantsShow answer & explanation →
Q27.
How many chromatids are present in a single bivalent (tetrad) during meiosis I?
A TwoB ThreeC FourD EightShow answer & explanation →
Q29.
Colchicine arrests dividing cells at metaphase because it:
A Prevents spindle fibre formationB Speeds up DNA replicationC Blocks DNA repair enzymesD Triggers programmed cell deathShow answer & explanation →
Q30.
The two sister chromatids of a chromosome are held together at the:
A TelomereB CentromereC Kinetochore fibreD ChiasmaShow answer & explanation →
Q31.
The G<sub>2</sub> checkpoint ensures:
A DNA is replicated without errors before mitosisB Cells have accumulated enough stored nutrientsC The mitotic spindle apparatus is largely assembledD Cytokinesis has been completed successfullyShow answer & explanation →
Q32.
Kinetochores are protein complexes that:
A Break double-stranded DNA at specific replication originsB Attach spindle microtubules to chromosomes at centromeresC Produce ATP via oxidative phosphorylation during divisionD Form the new cell plate during plant cytokinesisShow answer & explanation →
Q33.
MPF (Maturation Promoting Factor) promotes:
A DNA repair following ultraviolet radiation damageB Entry into mitosis (G<sub>2</sub> to M transition)C Cytokinesis and cleavage furrow formationD G<sub>1</sub> arrest in response to growth factor withdrawalShow answer & explanation →
Q34.
Endoreduplication results in:
A Two genetically normal, diploid daughter cellsB Polyploid cells (multiple sets of chromosomes)C Complete absence of any cell division eventD Only repair of damaged DNA without divisionShow answer & explanation →
Q35.
Karyokinesis refers to:
A Cytoplasm divisionB Nuclear divisionC Chromosome condensationD Spindle formationShow answer & explanation →
Q36.
Nondisjunction during meiosis I results in:
A One extra chromosome appearing in both resulting gametesB Gametes with both homologs or neither (n+1 and n-1)C Largely normal gametes with the correct chromosome numberD Mainly a single chromosome remaining per resulting cellShow answer & explanation →
Q37.
Down syndrome (Trisomy 21) is caused by:
A Deletion of part of chromosome 21 during meiosisB Extra copy of chromosome 21 (nondisjunction)C Translocation of chromosome 14 onto another chromosomeD Loss of one sex chromosome during gamete formationShow answer & explanation →
Q38.
Cyclin proteins control the cell cycle by:
A Directly cutting and degrading chromosomal DNA strandsB Activating Cdks (cyclin-dependent kinases) at specific stagesC Forming and polymerizing the mitotic spindle fibersD Causing chromosome condensation independently of CdksShow answer & explanation →
Q39.
Chiasmata are visible sites of:
A Sites of further chromosome condensation in metaphaseB Crossing over (genetic recombination) in Prophase IC Points of spindle microtubule attachment to kinetochoresD Sites of nuclear envelope breakdown in prophaseShow answer & explanation →
Q40.
Which cancer suppressor gene is mutated in many cancers?
A BRCA1 mainly, among tumour suppressorsB p53 (the guardian of the genome)C Oncogenes such as RAS and MYCD APC mainly, among tumour suppressorsShow answer & explanation →
Q41.
During meiosis II, sister chromatids separate similar to:
A Meiosis I anaphase separationB Mitosis anaphase (anaphase II)C Prophase I synapsis stageD Metaphase I alignment stageShow answer & explanation →
Q42.
Spindle assembly checkpoint monitors:
A Completion of DNA replication during S phaseB Correct attachment of all chromosomes to spindle fibersC Reformation of the nuclear envelope after mitosisD Completion of cytokinesis and cell separationShow answer & explanation →
Q43.
Telomere shortening is associated with:
A Uncontrolled cancer cell growth and divisionB Normal cellular aging and senescenceC Faster DNA replication during early developmentD Chromosome condensation before cell divisionShow answer & explanation →
Q44.
Amitosis is:
A Indirect cell division involving full spindle formationB Direct cell division (simple fission, no spindle)C Cell division occurring without any prior DNA replicationD A process found mainly in plant cells specificallyShow answer & explanation →
Q45.
The mitotic index is used to measure:
A The overall physical size of individual dividing cellsB Proportion of cells in mitosis (used in cancer diagnosis)C The rate of DNA synthesis occurring during interphaseD The total number of chromosomes present per cellShow answer & explanation →
Q46.
Recombination frequency between two genes indicates:
A The physical size of a chromosome in base pairsB Distance between genes on the same chromosomeC The total number of alleles present at a locusD The haploid chromosome number of the speciesShow answer & explanation →
Q47.
Cells that have left the cell cycle to perform specialized functions are in:
A G<sub>1</sub> phase, preparing for DNA synthesisB S phase, during DNA synthesisC G<sub>0</sub> phase (quiescent state)D G<sub>2</sub> phase, preparing for mitosisShow answer & explanation →
Q48.
During zygotene of meiosis I, homologous chromosomes:
A Separate largely from their homologous partnerB Undergo crossing over and exchange genetic materialC Begin to pair (synapsis starts)D Largely condense into visible compact structuresShow answer & explanation →
Q49.
Turner syndrome (45,X) results from:
A An extra X chromosome present in the karyotypeB Missing X chromosome (monosomy X: nondisjunction)C An extra Y chromosome present in the karyotypeD Trisomy of chromosome 21 (Down syndrome)Show answer & explanation →
Q50.
Actin and myosin are involved in which step of cell division?
A Chromosome condensation during prophaseB Spindle assembly during prometaphaseC Cytokinesis (cleavage furrow formation)D DNA replication during S phaseShow answer & explanation →
Hard - 25 questions Q52.
Meiosis II resembles mitosis but differs from it in that meiosis II:
A Pairs homologous chromosomesB Halves the chromosome numberC Involves crossing overD Begins with haploid cellsShow answer & explanation →
Q53.
A cell that fails the G1/S checkpoint because of DNA damage will normally:
A Halt until its DNA is repairedB Immediately enter mitosisC Duplicate its DNA fasterD Fuse with a neighbouring cellShow answer & explanation →
Q54.
The haploid products of meiosis are important because, on fertilisation, they:
A Double the chromosome number each generationB Restore the diploid number at fertilisationC Prevent all genetic variationD Undergo further meiosis at onceShow answer & explanation →
Q55.
Crossing over between homologous chromosomes is significant because it:
A Increases the chromosome numberB Keeps offspring genetically identicalC Generates new gene combinationsD Repairs broken spindle fibresShow answer & explanation →
Q56.
Aurora kinase B is involved in:
A Initiating new rounds of DNA replication at originsB Chromosome segregation error correction at kinetochoresC Assembling the bipolar mitotic spindle apparatusD Triggering breakdown of the nuclear envelopeShow answer & explanation →
Q57.
The SAC (spindle assembly checkpoint) is satisfied when:
A Every chromosome has largely condensed in preparation for upcoming division in typical laboratory settingsB Every kinetochore has tension from being attached to microtubules from opposite polesC Cytokinesis has already begun and the cleavage furrow is actively forming under usual circumstancesD DNA replication has largely completed across the entire genome sequence according to most researchersShow answer & explanation →
Q58.
Securin prevents premature sister chromatid separation by:
A Forming a direct physical bridge between sister chromatidsB Inhibiting separase (which would cleave cohesin)C Nucleating spindle microtubules at the centrosomeD Adding phosphate groups onto condensin II subunitsShow answer & explanation →
Q59.
The retinoblastoma protein (Rb) controls the cell cycle by:
A Cleaving caspase substrates directly to dismantle the nuclear envelope and trigger apoptosisB Binding E2F transcription factors, blocking S phase entry until phosphorylated by Cyclin D/Cdk4C Anchoring kinetochores to spindle microtubules to satisfy the metaphase checkpointD Recruiting nucleotide excision repair enzymes to sites of UV-induced DNA damageShow answer & explanation →
Q60.
Aneuploidy most commonly results from:
A Failure of enzymatic DNA repair machinery to fix existing damageB Spindle assembly checkpoint failure causing chromosome mis-segregationC Excessive, uncontrolled rounds of DNA replication occurring repeatedlyD Endoreduplication occurring alone without any subsequent cell divisionShow answer & explanation →
Q61.
The transition from metaphase to anaphase in mitosis requires:
A Cyclin B synthesis occurring continuously throughout the entirety of mitosisB APC/C (anaphase-promoting complex) activation by Cdc20, degrading cyclin B and securinC Activation of CDK1 at the G<sub>2</sub> to M phase boundary without any further checkpoint regulation required afterwardD Complete assembly of an entirely new mitotic spindle built independently at each subsequent round of divisionShow answer & explanation →
Q62.
Merotelic attachment is dangerous in cell division because:
A It physically prevents the completion of DNA replication occurring at the start of every single S phase cycleB One kinetochore is attached to microtubules from BOTH poles, risking lagging chromosomes in anaphaseC It physically blocks formation of the mitotic spindle by sequestering free tubulin subunits in the cytoplasmD It causes cytokinesis to begin prematurely before anaphase triggering furrow ingression while chromosomes are still movingShow answer & explanation →
Q63.
Telomerase activity is high in:
A Differentiated somatic cells throughout the bodyB Cancer cells and embryonic stem cellsC Mainly neurons within the central nervous systemD Mainly liver cells involved in regenerationShow answer & explanation →
Q64.
Condensin I and II differ in:
A Their physical location upon the chromosome arms alone, with no other functional distinction, with both complexes otherwise performing identical molecular roles throughout the entire cell cycleB Condensin I works in cytoplasm during mitosis; condensin II works in nucleus from G<sub>2</sub> onward for different aspects of chromosome architectureC Their relative ATP requirements during chromosome condensation, with condensin II needing far more, despite both complexes using the same SMC ATPase core to drive their condensation activityD The particular tissue types and cell lineages in which each complex is found expressed, even though both are ubiquitously expressed across essentially all dividing somatic cell typesShow answer & explanation →
Q65.
The pachytene checkpoint in meiosis monitors:
A Overall chromosome condensation status during prophaseB Synapsis completion and DNA double-strand break repairC Correct assembly of the meiotic spindle apparatusD Completion of cytoplasmic division during telophaseShow answer & explanation →
Q66.
Proteolysis of geminin at the end of mitosis allows:
A Further condensation of chromosomes ahead of the next cell division in the majority of cases studiedB Pre-replication complex (pre-RC) assembly licensing new DNA replication in G<sub>1</sub>C Disassembly of the spindle apparatus shortly following anaphase onset as widely reportedD Formation of the cleavage furrow during the cytokinesis process in standard practiceShow answer & explanation →
Q67.
Which kinase phosphorylates histone H3 at Serine 10 during mitosis?
A CDK1B Aurora B kinaseC Polo-like kinase 1D ATM kinaseShow answer & explanation →
Q68.
Cohesion between sister chromatids is established during:
A Prophase, prior to S phaseB S phase (DNA replication)C Metaphase, before anaphaseD G<sub>1</sub> phase, before S phaseShow answer & explanation →
Q69.
In meiosis, the protein SYCP3 is a component of:
A A structural protein component of the kinetochore complex structureB The synaptonemal complex (SC) that forms between homologs in Prophase IC A motor protein component of the meiotic spindle apparatus itselfD A channel protein embedded within the nuclear pore complex structureShow answer & explanation →
Q70.
Gene conversion during meiotic recombination results in:
A An exactly equal, reciprocal exchange of DNA occurring between homologsB Non-reciprocal transfer: one allele replaced by sequence from homologC A complete deletion of one homolog's entire chromosomal segmentD An inversion of a chromosomal segment occurring relative to its homologShow answer & explanation →
Q71.
The Holliday junction in recombination is:
A A specific site along the chromosome where double-strand breaks occur before any strand invasion or branch migration ever takes place thereB A four-way DNA junction formed during crossing-over (resolved to form crossover or non-crossover products)C A multi-subunit protein complex that mediates chromosome cohesion composed of cohesin subunits rather than any recombining DNA strandsD A chromatin modification that marks regions destined for recombination deposited well before meiosis begins, unrelated to active strand exchangeShow answer & explanation →
Q72.
Polo-like kinase 1 (PLK1) functions in:
A Initiating the very first round of DNA replication at origins by recruiting licensing factors to the unfired pre-RC complexesB Multiple mitotic steps: centrosome maturation, APC/C activation, kinetochore function, cytokinesisC Driving chromosome pairing and synapsis specifically during meiosis I via direct loading of SYCP proteins onto paired homologsD Maintaining the G<sub>1</sub> interphase checkpoint arrest exclusively through sustained inhibition of cyclin-dependent kinase activityShow answer & explanation →
Q73.
Chromosomal instability (CIN) in cancer cells is linked to:
A An excess amount of active telomerase enzyme present within the cellB Centrosome amplification and defective SAC leading to ongoing mis-segregationC The accumulation of point mutations alone, without any other cellular defectD Excessive DNA methylation occurring broadly across the entire genomeShow answer & explanation →
Q74.
The abscission step of cytokinesis in animal cells involves:
A Inward movement and ingression of the actomyosin cleavage furrow itselfB Plasma membrane fusion and cutting at the midbody region (ESCRT machinery)C Complete disassembly of the entire mitotic spindle apparatus structureD Reformation of the nuclear envelope around the segregated chromosomesShow answer & explanation →
Q75.
Mitotic slippage occurs when:
A Chromosomes that largely fail to condense properly before mitosis begins under most conditions encounteredB Cells exit mitosis without completing cell division (due to slow APC/C activation) and become aneuploidC The spindle assembly checkpoint becomes unusually and abnormally stringent over time as frequently observed in practiceD Cytokinesis alone fails while chromosome segregation otherwise proceeds normally in many documented casesShow answer & explanation →