NCERT NEET Biology English Medium Part-1 | Chapter 10: Cell Cycle and Cell Division.

NCERT NEET Biology English Medium Part-1 | Chapter 10 : Cell Cycle And Cell Division.

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Question 1: Which of the following statements correctly describes the duration of the interphase in a typical human cell cycle?

1. a) It lasts for less than 5% of the total duration of the cell cycle.
2. b) It lasts for exactly 50% of the total duration of the cell cycle.
3. c) It lasts for more than 95% of the total duration of the cell cycle.
4. d) It takes about 1 hour out of a 24-hour cycle.

Answer: c.

Question 2: If the initial amount of DNA in a cell is denoted as 2C, what will be the amount of DNA after the S phase?

1. a) C.
2. b) 2C.
3. c) 4C.
4. d) 8C.

Answer: c.

Question 3: A diploid cell has 16 chromosomes at the G1 phase. How many chromosomes will it have after the S phase is completed?

8. a) 8.
9. b) 16.
10. c) 32.
11. d) 64.

Answer: b.

Question 4: During which phase of the cell cycle do cells exit the G1 phase to enter an inactive state called the quiescent stage?

1. a) S phase.
2. b) G2 phase.
3. c) G0 phase.
4. d) M phase.

Answer: c.

Question 5: Which of the following events occurs in the cytoplasm of animal cells during the S phase?

1. a) DNA replication.
2. b) Condensation of chromosomes.
3. c) Centriole duplication.
4. d) Formation of the cell plate.

Answer: c.

Question 6: In a human cell culture dividing every 24 hours, approximately how long does the actual cell division (M phase) last?

1. a) 90 minutes.
2. b) 1 hour.
3. c) 12 hours.
4. d) 23 hours.

Answer: b.

Question 7: Which of the following structures is absent in cells viewed under a microscope at the end of prophase?

1. a) Golgi complexes.
2. b) Endoplasmic reticulum.
3. c) Nucleolus.
4. d) All of the above.

Answer: d.

Question 8: The morphology of chromosomes is most easily and clearly studied during which stage of mitosis?

1. a) Prophase.
2. b) Metaphase.
3. c) Anaphase.
4. d) Telophase.

Answer: b.

Question 9: What are the small disc-shaped structures at the surface of the centromeres called, which serve as attachment sites for spindle fibres?

1. a) Asters.
2. b) Chiasmata.
3. c) Kinetochores.
4. d) Centrosomes.

Answer: c.

Question 10: The plane of alignment of the chromosomes at the equator during metaphase is referred to as the:

1. a) Equatorial axis.
2. b) Metaphase plate.
3. c) Cleavage furrow.
4. d) Spindle equator.

Answer: b.

Question 11: Which crucial event characterises the onset of anaphase in mitosis?

1. a) Condensation of chromatin.
2. b) Attachment of spindle fibres to kinetochores.
3. c) Splitting of centromeres and separation of chromatids.
4. d) Decondensation of chromosomes at poles.

Answer: c.

Question 12: As each chromosome moves away from the equatorial plate during anaphase, what is the orientation of its arms?

1. a) Leading towards the pole.
2. b) Trailing behind the centromere.
3. c) Directed towards the equator.
4. d) Parallel to the spindle fibres.

Answer: b.

Question 13: During which stage do chromosomes cluster at opposite spindle poles and lose their identity as discrete elements?

1. a) Prophase.
2. b) Metaphase.
3. c) Anaphase.
4. d) Telophase.

Answer: d.

Question 14: In plant cells, cytokinesis involves the formation of a simple precursor known as the cell-plate. What does this cell-plate represent?

1. a) Primary cell wall.
2. b) Secondary cell wall.
3. c) Middle lamella.
4. d) Plasma membrane.

Answer: c.

Question 15: The condition where karyokinesis is not followed by cytokinesis, leading to a multinucleate state, is called a:

1. a) Plasmodium.
2. b) Syncytium.
3. c) Coenocyte.
4. d) Symplast.

Answer: b.

Question 16: An example of a syncytium formed due to the failure of cytokinesis after karyokinesis is:

1. a) Animal liver cells.
2. b) Onion root tip cells.
3. c) Liquid endosperm in coconut.
4. d) Epidermal cells of leaves.

Answer: c.

Question 17: Which of the following is a significant contribution of mitosis in living organisms?

1. a) Introduction of genetic variation.
2. b) Reduction of chromosome number.
3. c) Restoration of the nucleo-cytoplasmic ratio.
4. d) Formation of haploid gametes.

Answer: c.

Question 18: In which of the following organisms can mitotic division be seen in haploid cells?

1. a) Adult humans.
2. b) Male honey bees.
3. c) Higher animals.
4. d) All vertebrates.

Answer: b.

Question 19: Meiosis ensures the production of which phase in the life cycle of sexually reproducing organisms?

1. a) Diploid phase.
2. b) Haploid phase.
3. c) Triploid phase.
4. d) Polyploid phase.

Answer: b.

Question 20: How many sequential cycles of nuclear and cell division does meiosis involve?

1. a) One.
2. b) Two.
3. c) Three.
4. d) Four.

Answer: b.

Question 21: How many cycles of DNA replication occur during the entire process of meiosis?

1. a) Zero.
2. b) One.
3. c) Two.
4. d) Four.

Answer: b.

Question 22: During which specific stage of Prophase I does the pairing of homologous chromosomes (synapsis) occur?

1. a) Leptotene.
2. b) Zygotene.
3. c) Pachytene.
4. d) Diplotene.

Answer: b.

Question 23: The complex formed by a pair of synapsed homologous chromosomes is called a:

1. a) Monad.
2. b) Bivalent or tetrad.
3. c) Kinetochore.
4. d) Axoneme.

Answer: b.

Question 24: Crossing over occurs between which chromatids of the homologous chromosomes?

1. a) Sister chromatids.
2. b) Non-sister chromatids.
3. c) Maternal chromatids only.
4. d) Paternal chromatids only.

Answer: b.

Question 25: The enzyme responsible for the process of crossing over during Pachytene is:

1. a) DNA polymerase.
2. b) Ligase.
3. c) Recombinase.
4. d) Helicase.

Answer: c.

Question 26: The X-shaped structures formed due to the dissolution of the synaptonemal complex, except at the sites of crossovers, are called:

1. a) Bivalents.
2. b) Tetrads.
3. c) Chiasmata.
4. d) Centromeres.

Answer: c.

Question 27: Which stage of Prophase I is characterized by the terminalisation of chiasmata?

1. a) Zygotene.
2. b) Pachytene.
3. c) Diplotene.
4. d) Diakinesis.

Answer: d.

Question 28: In oocytes of some vertebrates, which stage of Prophase I can last for months or years?

1. a) Leptotene.
2. b) Zygotene.
3. c) Diplotene.
4. d) Diakinesis.

Answer: c.

Question 29: During Metaphase I, what aligns on the equatorial plate?

1. a) Unpaired chromosomes.
2. b) Bivalent chromosomes.
3. c) Sister chromatids.
4. d) Single chromatids.

Answer: b.

Question 30: What separates during Anaphase I of meiosis?

1. a) Sister chromatids.
2. b) Homologous chromosomes.
3. c) Non-sister chromatids.
4. d) Centromeres.

Answer: b.

Question 31: During Anaphase I, what happens to the sister chromatids?

1. a) They separate and move to opposite poles.
2. b) They undergo crossing over.
3. c) They remain associated at their centromeres.
4. d) They attach to the cell plate.

Answer: c.

Question 32: The stage between the two meiotic divisions is called:

1. a) Interphase.
2. b) Interkinesis.
3. c) Intraphase.
4. d) Cytokinesis.

Answer: b.

Question 33: Interkinesis is generally short-lived and is followed immediately by:

1. a) Prophase I.
2. b) Prophase II.
3. c) Metaphase II.
4. d) S phase.

Answer: b.

Question 34: Is there DNA replication during interkinesis?

1. a) Yes, the DNA doubles again.
2. b) No, there is no DNA replication during interkinesis.
3. c) Yes, but only in animal cells.
4. d) Yes, but only for mitochondrial DNA.

Answer: b.

Question 35: Meiosis II is most similar to which other cellular process?

1. a) Meiosis I.
2. b) Normal mitosis.
3. c) Cytokinesis.
4. d) DNA replication.

Answer: b.

Question 36: What separates during Anaphase II of meiosis?

1. a) Homologous chromosomes.
2. b) Bivalents.
3. c) Sister chromatids.
4. d) Tetrads.

Answer: c.

Question 37: At the end of Meiosis II, how many cells are formed from a single parent cell?

1. a) Two diploid cells.
2. b) Four diploid cells.
3. c) Two haploid cells.
4. d) Four haploid cells.

Answer: d.

Question 38: Which of the following introduces genetic variation within a population?

1. a) Mitosis.
2. b) Crossing over during meiosis.
3. c) DNA replication in S phase.
4. d) Cytokinesis.

Answer: b.

Question 39: Mitosis is an equational division, whereas Meiosis I is a:

1. a) Multiplicational division.
2. b) Reductional division.
3. c) Symmetrical division.
4. d) Conservative division.

Answer: b.

Question 40: Yeast can progress through the cell cycle in approximately how much time?

1. a) 24 hours.
2. b) 90 minutes.
3. c) 12 hours.
4. d) 48 hours.

Answer: b.

Question 41: Which of the following phases is NOT a part of Interphase?

1. a) G1 phase.
2. b) S phase.
3. c) G2 phase.
4. d) M phase.

Answer: d.

Question 42: What happens to the nuclear envelope during early prophase of mitosis?

1. a) It replicates.
2. b) It remains intact.
3. c) It begins to disintegrate.
4. d) It merges with the plasma membrane.

Answer: c.

Question 43: In animal cells, the mitotic apparatus consists of two asters together with:

1. a) The nucleolus.
2. b) The Golgi complex.
3. c) Spindle fibres.
4. d) Chromatin networks.

Answer: c.

Question 44: The progressive process of karyokinesis makes it difficult to:

1. a) See chromosomes.
2. b) Draw clear-cut lines between its various stages.
3. c) Identify the equatorial plate.
4. d) Count the number of cells.

Answer: b.

Question 45: What marks the completion of metaphase in mitosis?

1. a) Disappearance of the nucleolus.
2. b) Alignment of chromosomes at the equator.
3. c) Splitting of centromeres.
4. d) Re-formation of the nuclear envelope.

Answer: b.

Question 46: A cell with 24 chromosomes undergoes meiosis. How many chromosomes will each daughter cell have at the end of Meiosis I?

48. a) 48.
49. b) 24.
50. c) 12.
51. d) 6.

Answer: c.

Question 47: A cell with 24 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have?

48. a) 48.
49. b) 24.
50. c) 12.
51. d) 6.

Answer: b.

Question 48: Which structures pull the chromatids towards opposite poles during anaphase?

1. a) Aster rays.
2. b) Kinetochore microtubules (spindle fibres).
3. c) Centrioles.
4. d) Actin filaments.

Answer: b.

Question 49: The term "karyokinesis" refers to the division of the:

1. a) Cytoplasm.
2. b) Nucleus.
3. c) Cell wall.
4. d) Mitochondria.

Answer: b.

Question 50: The term "cytokinesis" refers to the division of the:

1. a) Cytoplasm.
2. b) Nucleus.
3. c) Endoplasmic reticulum.
4. d) Chromosomes.

Answer: a.

Question 51: In plants, mitotic divisions resulting in continuous growth throughout their life occur in:

1. a) Permanent tissues.
2. b) Meristematic tissues.
3. c) Epidermal tissues.
4. d) Vascular tissues.

Answer: b.

Question 52: Apical and lateral cambium are examples of tissues that undergo constant:

1. a) Meiosis.
2. b) Mitosis.
3. c) Amitosis.
4. d) Plasmolysis.

Answer: b.

Question 53: Cells of the upper layer of the epidermis and the lining of the gut are constantly replaced through:

1. a) Meiosis.
2. b) Mitosis.
3. c) Senescence.
4. d) Apoptosis.

Answer: b.

Question 54: Which phase of Prophase I is characterized by the compaction of chromosomes becoming visible under the light microscope?

1. a) Leptotene.
2. b) Zygotene.
3. c) Pachytene.
4. d) Diplotene.

Answer: a.

Question 55: The formation of the synaptonemal complex is associated with which stage?

1. a) Leptotene.
2. b) Zygotene.
3. c) Pachytene.
4. d) Diakinesis.

Answer: b.

Question 56: Recombination nodules appear during which stage of Prophase I?

1. a) Leptotene.
2. b) Zygotene.
3. c) Pachytene.
4. d) Diplotene.

Answer: c.

Question 57: During the transition to metaphase I, what represents the fully condensed state of meiotic chromosomes?

1. a) Zygotene.
2. b) Pachytene.
3. c) Diplotene.
4. d) Diakinesis.

Answer: d.

Question 58: By the end of which stage does the nucleolus disappear and the nuclear envelope break down in Meiosis I?

1. a) Zygotene.
2. b) Pachytene.
3. c) Diplotene.
4. d) Diakinesis.

Answer: d.

Question 59: During Telophase I, do the chromosomes completely disperse into a resting chromatin state?

1. a) Yes, they fully decondense.
2. b) No, they undergo some dispersion but do not reach the extremely extended state of the interphase nucleus.
3. c) Yes, they form an invisible network immediately.
4. d) No, they remain fully condensed throughout interkinesis.

Answer: b.

Question 60: What is the primary function of the spindle fibers during cell division?

1. a) Synthesize DNA.
2. b) Generate ATP.
3. c) Attach to kinetochores and move chromosomes.
4. d) Form the nuclear envelope.

Answer: c.

Question 61: If a cell at the G1 phase has a DNA content of 20 picograms, what will be its DNA content at G2 phase?

1. a) 10 picograms.
2. b) 20 picograms.
3. c) 40 picograms.
4. d) 80 picograms.

Answer: c.

Question 62: Which of the following happens to the chromosomes in the G1 phase?

1. a) They are actively replicated.
2. b) They condense into visible X-shapes.
3. c) They remain as single chromatids and the cell grows.
4. d) They align at the equator.

Answer: c.

Question 63: During cell cycle regulation, a cell that will no longer divide enters the G0 phase from the:

1. a) S phase.
2. b) G2 phase.
3. c) M phase.
4. d) G1 phase.

Answer: d.

Question 64: Mitosis is described as an equational division because:

1. a) It divides the cytoplasm equally.
2. b) The daughter cells have the same number of chromosomes as the parent cell.
3. c) The cell divides exactly in the middle.
4. d) It takes an equal amount of time for all phases.

Answer: b.

Question 65: Anaphase promoting complex (APC) is required for separation of sister chromatids. If APC is defective in a human cell, what will be the consequence?

1. a) Chromosomes will not condense.
2. b) Chromosomes will fail to align at the equator.
3. c) Sister chromatids will not separate.
4. d) Cytokinesis will occur prematurely.

Answer: c.

Question 66: In higher plants, polyploidy can be artificially induced by using:

1. a) Auxin.
2. b) Gibberellin.
3. c) Colchicine.
4. d) Cytokinin.

Answer: c.

Question 67: In a haplontic life cycle, zygotic meiosis results in the production of:

1. a) Diploid spores.
2. b) Haploid organisms.
3. c) Triploid endosperm.
4. d) Multinucleate syncytium.

Answer: b.

Question 68: If there is repeated replication of DNA without any cell division, it leads to:

1. a) Polyploidy.
2. b) Aneuploidy.
3. c) Haploidy.
4. d) Monosomy.

Answer: a.

Question 69: Which process restores the diploid phase in the life cycle of sexually reproducing organisms?

1. a) Meiosis.
2. b) Mitosis.
3. c) Fertilisation.
4. d) Crossing over.

Answer: c.

Question 70: Which phase of the cell cycle is marked by the initiation of condensation of chromosomal material?

1. a) Prophase.
2. b) Metaphase.
3. c) Anaphase.
4. d) Telophase.

Answer: a.

Question 71: The interphase is colloquially referred to as the "resting phase." Why is this term somewhat misleading?

1. a) Because the cell is dying during this phase.
2. b) Because the cell is metabolically highly active and preparing for division.
3. c) Because it is the shortest phase of the cell cycle.
4. d) Because actual cell division occurs rapidly during this phase.

Answer: b.

Question 72: A student observes onion root tip cells under a microscope and counts 16 chromosomes in a cell in the G1 phase. What is the expected DNA content (in terms of C) in this cell if the content after M phase is 2C?

1. a) 1C.
2. b) 2C.
3. c) 3C.
4. d) 4C.

Answer: b.

Question 73: Based on the previous question, what would be the DNA content and chromosome number of the same cell after the S phase?

1. a) 2C, 16 chromosomes.
2. b) 4C, 16 chromosomes.
3. c) 4C, 32 chromosomes.
4. d) 2C, 32 chromosomes.

Answer: b.

Question 74: During which stage do the two asters together with spindle fibres form the mitotic apparatus?

1. a) Interphase.
2. b) Prophase.
3. c) Anaphase.
4. d) Telophase.

Answer: b.

Question 75: The furrow in the plasma membrane of an animal cell during cytokinesis deepens and joins in the centre. This division mechanism is described as:

1. a) Centrifugal.
2. b) Centripetal.
3. c) Equatorial.
4. d) Longitudinal.

Answer: b.

Question 76: In plant cells, the cell plate grows outward to meet the existing lateral walls. This mechanism of cytokinesis is described as:

1. a) Centrifugal.
2. b) Centripetal.
3. c) Invagination.
4. d) Constriction.

Answer: a.

Question 77: The random distribution of homologous chromosomes between daughter cells during meiosis leads to:

1. a) Clonal expansion.
2. b) Genetic variation.
3. c) Polyploidy.
4. d) Mutation.

Answer: b.

Question 78: During which specific sub-stage of Prophase I does the crossing over actually complete?

1. a) Leptotene.
2. b) Zygotene.
3. c) Pachytene.
4. d) Diplotene.

Answer: c.

Question 79: The dissolution of the synaptonemal complex marks the beginning of which stage?

1. a) Zygotene.
2. b) Pachytene.
3. c) Diplotene.
4. d) Diakinesis.

Answer: c.

Question 80: What provides the physical basis for the law of independent assortment during meiosis?

1. a) Separation of sister chromatids in Anaphase II.
2. b) Random alignment of bivalents at the metaphase plate in Metaphase I.
3. c) Crossing over in Pachytene.
4. d) DNA replication in S phase.

Answer: b.

Question 81: Why is Meiosis II required after Meiosis I has already reduced the chromosome number?

1. a) To further reduce the chromosome number.
2. b) To separate the homologous chromosomes.
3. c) To separate the sister chromatids, converting dyads to monads.
4. d) To increase the amount of DNA in the cells.

Answer: c.

Question 82: Which of the following is true about the kinetochores during Metaphase I of meiosis?

1. a) Kinetochores of sister chromatids attach to spindle fibers from opposite poles.
2. b) Kinetochores of sister chromatids attach to spindle fibers from the same pole.
3. c) Kinetochores do not attach to spindle fibers during Metaphase I.
4. d) Kinetochores disintegrate during Metaphase I.

Answer: b.

Question 83: Which of the following correctly pairs the cell cycle phase with its major event?

1. a) G1 phase - DNA replication.
2. b) S phase - Cell division.
3. c) G2 phase - Preparation for mitosis, protein synthesis.
4. d) M phase - Cell growth.

Answer: c.

Question 84: In a diploid cell, what is the maximum number of alleles for a single autosomal gene present at the G2 phase?

1. a) 1.
2. b) 2.
3. c) 3.
4. d) 4.

Answer: d.

Question 85: The term "chiasmata" refers to the structures that are visible manifestations of:

1. a) Spindle fiber attachment.
2. b) Chromosome condensation.
3. c) Crossing over.
4. d) Centromere splitting.

Answer: c.

Question 86: If a cell has 10 bivalents in Prophase I, what is the total number of chromosomes in the diploid parent cell?

5. a) 5.
6. b) 10.
7. c) 20.
8. d) 40.

Answer: c.

Question 87: At what stage of the cell cycle is the cell's DNA content highest?

1. a) Early G1.
2. b) G0.
3. c) Late G2.
4. d) End of Telophase.

Answer: c.

Question 88: The nucleolus and nuclear envelope reappear during which stage of meiosis?

1. a) Anaphase I.
2. b) Telophase I.
3. c) Prophase II.
4. d) Metaphase II.

Answer: b.

Question 89: Which statement accurately describes the chromatids moving to the poles during Anaphase II?

1. a) They are genetically identical to each other.
2. b) They consist of non-sister chromatids only.
3. c) They may not be genetically identical due to crossing over in Prophase I.
4. d) They are bivalents.

Answer: c.

Question 90: How does a cell in the G0 phase differ from a cell in the G1 phase?

1. a) The G0 cell has half the DNA content of the G1 cell.
2. b) The G0 cell is metabolically inactive.
3. c) The G0 cell has exited the cell cycle and is not actively dividing.
4. d) The G0 cell contains duplicated chromosomes.

Answer: c.

Question 91: The cell division in male honey bees occurs by mitosis because:

1. a) They are diploid organisms.
2. b) They undergo spontaneous mutations.
3. c) They are haploid organisms developing from unfertilized eggs.
4. d) They lack a true nucleus.

Answer: c.

Question 92: A typical eukaryotic cell cycle represents a highly coordinated process. Errors in DNA replication during the S phase would most likely trigger a checkpoint at:

1. a) The G1/S transition.
2. b) The G2/M transition.
3. c) The metaphase/anaphase transition.
4. d) Cytokinesis.

Answer: b.

Question 93: During which stage of meiosis does the splitting of the centromere occur?

1. a) Anaphase I.
2. b) Metaphase I.
3. c) Anaphase II.
4. d) Telophase II.

Answer: c.

Question 94: What is the main outcome of the equational division in meiosis?

1. a) Reduction of chromosome number by half.
2. b) Separation of homologous chromosomes.
3. c) Separation of sister chromatids into four haploid cells.
4. d) Formation of bivalents.

Answer: c.

Question 95: Which of the following organelles' duplication is closely synchronized with DNA replication in the cell cycle of animal cells?

1. a) Mitochondria.
2. b) Chloroplast.
3. c) Centriole.
4. d) Ribosome.

Answer: c.

Question 96: What is the characteristic feature of the Diplotene stage of Prophase I?

1. a) Terminalisation of chiasmata.
2. b) Dissolution of the synaptonemal complex.
3. c) Synapsis of homologous chromosomes.
4. d) Appearance of recombination nodules.

Answer: b.

Question 97: Chromosomal mutations can arise due to abnormalities in cell division. Why might polyploidy be advantageous in some agricultural plants?

1. a) It strictly prevents crossing over.
2. b) It often leads to larger cell size, robust growth, and increased yield.
3. c) It makes the plants haploid and easier to breed.
4. d) It accelerates the cell cycle.

Answer: b.

Question 98: Which organelle remains visible during late prophase when observed under a standard light microscope?

1. a) Golgi apparatus.
2. b) Endoplasmic reticulum.
3. c) Nucleolus.
4. d) None of the above.

Answer: d.

Question 99: If the DNA content of a human cell in the G1 phase is 2n, what would be the DNA content and chromosome number in Anaphase of mitosis?

1. a) 4n DNA, 46 chromosomes.
2. b) 4n DNA, 92 chromosomes.
3. c) 2n DNA, 46 chromosomes.
4. d) 2n DNA, 92 chromosomes.

Answer: b.

Question 100: Which of the following best defines a "bivalent"?

1. a) A single chromosome with two sister chromatids.
2. b) Two homologous chromosomes consisting of four chromatids in total.
3. c) Two non-homologous chromosomes aligning together.
4. d) Four distinct chromosomes during anaphase.

Answer: b.

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