Cell Cycle and Cell Division: count it right, mark it right

Free questions

30 solved MCQs, answer marked and reasoning written out

Every question below is free to read — no sign-up, no email. 3 of them are real questions from past NEET papers. The other 186 questions in this chapter are in the book and in practice access.

1. Q1 Multi-statement analysis

   At the end of prophase, cells do NOT show: (i) golgi complexes (ii) endoplasmic reticulum (iii) nucleolus (iv) nuclear envelope. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.Three
   4. 4.FourCorrect answer

   Why option 4 is the answer

   The trap: All four disappear by the end of prophase.

   What this is testing: which structures are gone by the time prophase ends.

   All four are correct. By late prophase the golgi complex, the endoplasmic reticulum, the nucleolus and the nuclear envelope have all disappeared, clearing the way for the spindle to take over the cell's centre.

   So all four are correct. There is no trap planted here — when a question lists everything that vanishes together at one landmark stage, resist the urge to assume one item must be an exception.

   Golgi, ER, nucleolus and nuclear envelope all vanish by late prophase. The cell dismantles its interior to make room for the spindle.

   NCERT Class 11 Biology, page 123

2. Q2 Multi-statement analysis

   Diplotene: (i) begins with the dissolution of the synaptonemal complex (ii) homologous chromosomes tend to separate except at the sites of crossovers (iii) the X-shaped structures at these sites are chiasmata (iv) in oocytes of some vertebrates diplotene can last for months or years. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.Three
   4. 4.FourCorrect answer

   Why option 4 is the answer

   The trap: All four are correct.

   What this is testing: the sequence of events packed into diplotene.

   All four are correct. Diplotene opens with the synaptonemal complex dissolving, after which the homologues drift apart except at the points where they crossed over. Those X-shaped points are the chiasmata. And in some vertebrate oocytes, this single stage is famously stretched out over months or years while the egg waits.

   So all four are correct. Diplotene is unusually rich in named detail, and the question checks whether you hold all of it together rather than borrowing an event from an adjacent stage.

   Chiasmata are the visible evidence that crossing over happened. In some oocytes this stage lasts for months or years.

   NCERT Class 11 Biology, page 126

3. Q3 Multi-statement analysis

   Regarding syncytium: (i) it arises when karyokinesis is not followed by cytokinesis (ii) it is a multinucleate condition (iii) liquid endosperm in coconut is an example (iv) it results from cytokinesis without karyokinesis. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; the sequence is reversed in (iv), so it is wrong.

   What this is testing: the definition of a syncytium and a concrete NCERT example.

   (i) is correct. A syncytium forms when karyokinesis — nuclear division — happens without cytokinesis following it. (ii) is correct — the result is one cytoplasm holding many nuclei. (iii) is correct: the liquid endosperm of a coconut is the textbook example. (iv) is the trap. It reverses the sequence in (i): the missing step is cytokinesis after karyokinesis, not the other way round.

   So three are correct. The trap simply flips which of the two divisions is skipped — read the order carefully rather than pattern-matching the two familiar words.

   Nucleus divides, cytoplasm does not. Coconut water is the classic syncytium, with many nuclei in one mass.

   NCERT Class 11 Biology, page 124

4. Q4 Multi-statement analysis

   Prophase I is subdivided into: (i) leptotene (ii) zygotene (iii) pachytene (iv) diplotene (v) diakinesis. How many stages?

   1. 1.Two
   2. 2.Three
   3. 3.Four
   4. 4.FiveCorrect answer

   Why option 4 is the answer

   The trap: Prophase I has five sub-stages.

   What this is testing: simple recall of how many sub-stages make up prophase I.

   Prophase I is split into leptotene, zygotene, pachytene, diplotene and diakinesis — five named sub-stages in that fixed order.

   So the answer is (4) Five. There is no hidden trap in the count itself; the difficulty is purely in having all five names ready, since prophase I is stretched out and detailed enough that students sometimes shorten the list from memory.

   Leptotene, zygotene, pachytene, diplotene, diakinesis. Five stages, and prophase I is by far the longest part of meiosis.

   NCERT Class 11 Biology, page 126

5. Q5 Multi-statement analysis

   The quiescent stage (G0): (i) cells exit G1 to enter it (ii) such cells remain metabolically active (iii) such cells no longer proliferate unless required (iv) heart cells are an example of cells that do not appear to divide. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.Three
   4. 4.FourCorrect answer

   Why option 4 is the answer

   The trap: All four are correct.

   What this is testing: what the quiescent G0 stage really is, and one named example of it.

   All four are correct. Cells enter G0 by exiting G1 rather than proceeding to S phase; they remain metabolically active even though they are not dividing; they stay this way unless a specific need calls them back into the cycle; and adult heart cells are the standard example of cells that do not appear to divide further.

   So all four are correct. G0 is quiescent, not dead — every part of that idea is captured correctly here.

   G0 cells are active but not dividing. Heart and nerve cells stay there for life, which is why neither heals by replacement.

   NCERT Class 11 Biology, page 122

6. Q6 Multi-statement analysis

   Regarding growth and DNA synthesis: (i) cell growth in terms of cytoplasmic increase is a continuous process (ii) DNA synthesis occurs only during one specific stage of the cell cycle (iii) replicated chromosomes are distributed to daughter nuclei during cell division (iv) DNA synthesis is also a continuous process throughout the cycle. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; DNA synthesis is confined to the S phase, so (iv) is wrong.

   What this is testing: which processes in the cell cycle are continuous and which are confined to one stage.

   (i) is correct. Cytoplasmic growth runs continuously through the cycle. (ii) is correct — DNA synthesis, by contrast, is boxed into the S phase alone. (iii) is correct: once chromosomes have been replicated, cell division parcels them out to the daughter nuclei. (iv) is the trap. It contradicts (ii): DNA synthesis is NOT continuous — it happens only during S phase, not throughout the whole cycle.

   So three are correct. Growth and DNA synthesis are the two processes NCERT deliberately contrasts, and (iv) blurs that contrast back together.

   Growth is continuous, DNA synthesis is confined to one phase. That separation is what makes the cycle a cycle.

   NCERT Class 11 Biology, page 120

7. Q7 Multi-statement analysis

   Regarding the centrosome in mitosis: (i) it undergoes duplication during the S phase of interphase (ii) it begins to move towards opposite poles in prophase (iii) each centrosome radiates out microtubules called asters (iv) the two asters together with spindle fibres form the mitotic apparatus. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.Three
   4. 4.FourCorrect answer

   Why option 4 is the answer

   The trap: All four are correct.

   What this is testing: the centrosome's role in building the mitotic spindle.

   All four are correct. The centrosome duplicates during the S phase, well before division begins; in prophase the two copies start moving to opposite poles; each one then radiates out microtubules called asters; and together, the two asters with the spindle fibres between them make up the mitotic apparatus.

   So all four are correct. This traces one structure — the centrosome — through its whole story from duplication to spindle assembly, and every step of that story checks out.

   Centrosome duplicates in S, separates in prophase, and the two asters plus the spindle form the mitotic apparatus.

   NCERT Class 11 Biology, page 122

8. Q8 Multi-statement analysis

   The cell cycle: (i) is the sequence of events by which a cell duplicates its genome (ii) includes synthesis of the other constituents of the cell (iii) ends with division into two daughter cells (iv) is not under genetic control. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; the events of the cell cycle ARE under genetic control, so (iv) is wrong.

   What this is testing: what the cell cycle is, and whether it runs on its own.

   (i) is correct. The cell cycle is the sequence of events a cell goes through to duplicate its genome. (ii) is correct — it also covers making the cell's other components, not just DNA. (iii) is correct: the cycle ends with the cell splitting into two daughters. (iv) is the trap. The events of the cell cycle ARE under genetic control — they do not run randomly or outside the cell's own regulation.

   So three are correct. Calling a tightly checkpointed, regulated process 'not under genetic control' is the reversal this question is testing for.

   Duplicate the genome, build everything else, then divide. The cycle is tightly controlled, and loss of that control is what cancer is.

   NCERT Class 11 Biology, page 120

9. Q9 Assertion and Reason

   AssertionIn the human cell cycle, cell division proper lasts only about an hour.

   ReasonHuman cells in culture divide once in approximately every 24 hours.

   1. 1.Both A and R are true and R is the correct explanation of A
   2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
   3. 3.A is true but R is false
   4. 4.A is false but R is true

   Why option 2 is the answer

   The trap: Both are true of the human cell cycle; the 24-hour cycle length is a parallel fact and does not by itself explain the one-hour M phase.

   What this is testing: whether the length of the whole human cell cycle explains the length of just its M phase.

   A says cell division proper lasts about an hour in the human cycle. True. R says human cells in culture divide about once every 24 hours. Also true.

   Both are genuine facts about the human cell cycle, but the total cycle length does not explain why the M phase specifically takes an hour — they are two separate measurements. So the code is (2).

   The trap: numbers from the same topic feel linked; check whether one is actually the cause of the other; here neither line depends on the other.

   NCERT Class 11 Biology, page 121

10. Q10 Assertion and Reason

    AssertionThe chromosome number does not change during the S phase.

    ReasonDuring the S phase the DNA content per cell increases from 2C to 4C.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of the S phase; the doubling of DNA is a parallel fact and does not explain the constancy of chromosome number.

    What this is testing: whether the doubling of DNA content explains the constancy of chromosome number.

    A says the chromosome number does not change during S phase. True. R says the DNA content per cell rises from 2C to 4C during S phase. Also true.

    Both are correct, but R describes DNA content doubling, which is a separate fact running alongside chromosome number staying fixed — it does not explain why the number itself is unchanged. So the code is (2).

    The trap: DNA content and chromosome number move independently here; a true fact about one is not automatically the reason behind the other.

    NCERT Class 11 Biology, page 121

11. Q11 Assertion and Reason

    AssertionYeast can complete its cell cycle in about 90 minutes.

    ReasonHuman cells in culture divide once in approximately every 24 hours.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true durations for different organisms running in parallel; one does not explain the other.

    What this is testing: whether a fact about human cells explains a fact about yeast.

    A says yeast completes its cell cycle in about 90 minutes. True. R says human cells in culture divide about once every 24 hours. Also true.

    Both are genuine cycle-length facts from the chapter, but a duration in yeast cannot be explained by a duration in an unrelated organism. So the code is (2).

    The trap: pairing timing facts from different organisms in one question invites you to assume a link where none exists — check whether R is even about the same subject as A.

    NCERT Class 11 Biology, page 121

12. Q12 Assertion and Reason

    AssertionInterphase is not truly a resting phase.

    ReasonThe interphase lasts more than 95 per cent of the duration of the cell cycle.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of interphase; its long duration is a parallel fact and does not explain why it is metabolically busy rather than resting.

    What this is testing: whether interphase's long duration explains why it is not truly 'resting'.

    A says interphase is not truly a resting phase. True. R says interphase lasts more than 95 per cent of the cell cycle. Also true.

    Both are correct, but interphase being busy comes from what the cell does during it — replicating DNA, growing, preparing — not from how long it lasts. So the code is (2).

    The trap: duration and activity are different claims; a long phase is not automatically a busy one, even when both happen to be true here.

    NCERT Class 11 Biology, page 121

13. Q13 Assertion and Reason

    AssertionAt the end of prophase the nucleolus is no longer visible.

    ReasonCells at the end of prophase also do not show golgi complexes, endoplasmic reticulum and the nuclear envelope.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of late prophase; the disappearance of the other structures is a parallel observation and does not explain the loss of the nucleolus.

    What this is testing: whether one late-prophase disappearance explains another.

    A says the nucleolus is no longer visible by the end of prophase. True. R says the golgi complex, endoplasmic reticulum and nuclear envelope also disappear by then. Also true.

    Both are genuine late-prophase events happening side by side, but the loss of the other organelles does not cause the nucleolus specifically to vanish — they are a shared list of changes, not steps in a chain. So the code is (2).

    The trap: several true facts about the same moment in time look like one explaining another; check whether a causal link is actually claimed.

    NCERT Class 11 Biology, page 123

14. Q14 Assertion and Reason

    AssertionMeiosis involves two cycles of DNA replication and two cycles of nuclear division.

    ReasonMeiosis involves two sequential cycles of nuclear division but only a single cycle of DNA replication.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false; R is true.

    What this is testing: how many times DNA is copied during meiosis, against how many divisions follow.

    A says meiosis involves two cycles of DNA replication and two cycles of nuclear division. This is false — DNA is replicated only ONCE, before the two nuclear divisions begin. R says meiosis has two sequential cycles of nuclear division but only a single cycle of DNA replication. This is true.

    So A is false and R is true, giving code (4).

    The trap: it feels natural to pair 'two divisions' with 'two replications', but meiosis's whole reducing effect depends on replicating only once for those two divisions.

    NCERT Class 11 Biology, page 125

15. Q15 Assertion and Reason

    AssertionMitosis produces two daughter cells with half the chromosome number of the parent.

    ReasonMitosis is an equational division in which the chromosome number of the parent is conserved in the daughter cells.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — that describes meiosis; R is true.

    What this is testing: whether the description given actually matches mitosis or its opposite.

    A says mitosis produces two daughter cells with half the parent's chromosome number. This is false — that halving describes meiosis; mitosis conserves the number. R says mitosis is an equational division that conserves the chromosome number. This is true.

    So A is false and R is true, giving code (4).

    The trap: A quietly swaps in meiosis's defining outcome while keeping the word 'mitosis' — read past the label to the actual claim being made.

    NCERT Class 11 Biology, page 122

16. Q16 Assertion and Reason

    AssertionThe chromosome number doubles from 2n to 4n during the S phase.

    ReasonDuring the S phase the DNA content doubles from 2C to 4C while the chromosome number remains 2n.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false; R is true.

    What this is testing: whether the chromosome number changes during S phase, and by how much.

    A says the chromosome number doubles from 2n to 4n during S phase. This is false — the number stays at 2n. R says DNA content doubles from 2C to 4C while the chromosome number remains 2n. This is true.

    So A is false and R is true, giving code (4).

    The trap: S phase does double something, and A simply attaches that doubling to the wrong quantity — chromosome number, instead of DNA content.

    NCERT Class 11 Biology, page 121

17. Q17 Assertion and Reason

    AssertionDiplotene can last for months or years in the oocytes of some vertebrates.

    ReasonDiplotene begins with the dissolution of the synaptonemal complex.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of diplotene; the dissolution of the complex is a parallel event and does not explain the prolonged duration.

    What this is testing: whether diplotene's long duration is explained by the loss of the synaptonemal complex.

    A says diplotene can last months or years in the oocytes of some vertebrates. True. R says diplotene begins with the dissolution of the synaptonemal complex. Also true.

    Both are genuine diplotene facts, but the complex dissolving marks the start of the stage — it does not explain why the stage itself then gets held open for so long. So the code is (2).

    The trap: two true facts about the same stage do not automatically explain each other; check whether R actually accounts for the duration in A, or is just another feature of the same stage.

    NCERT Class 11 Biology, page 126

18. Q18 Statement I and Statement II

    Statement IDuring the G1 phase the cell replicates its DNA.

    Statement IIDuring the S phase the cell is metabolically active but does not grow.

    1. 1.Both Statement I and Statement II are correct
    2. 2.Both Statement I and Statement II are incorrectCorrect answer
    3. 3.Statement I is correct but Statement II is incorrect
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 2 is the answer

    The trap: Both incorrect — DNA replication occurs in S phase, and growth continues through interphase.

    What this is testing: assigning DNA replication and growth to the correct phase.

    Statement I: the cell replicates its DNA during G1. Wrong — replication is confined to the S phase, which comes after G1.
    Statement II: during S phase the cell is active but does not grow. Also wrong — growth continues right through S phase; it is DNA content, not cell growth, that is special to this phase.

    Both are incorrect, so the answer is (2).

    The trap: each statement takes a real S-phase or G1 fact and shifts it to the wrong phase or the wrong process — check both the 'what' and the 'when' separately.

    NCERT Class 11 Biology, page 121

19. Q19 Statement I and Statement II

    Statement IThe cell-plate represents the middle lamella between the walls of two adjacent cells.

    Statement IIA syncytium arises when karyokinesis is not followed by cytokinesis.

    1. 1.Both Statement I and Statement II are correctCorrect answer
    2. 2.Both Statement I and Statement II are incorrect
    3. 3.Statement I is correct but Statement II is incorrect
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 1 is the answer

    The trap: Both statements are correct.

    What this is testing: two separate facts about cell division outcomes, checked independently.

    Statement I: the cell-plate represents the middle lamella between the walls of two adjacent cells. Correct.
    Statement II: a syncytium arises when karyokinesis is not followed by cytokinesis. Also correct.

    Both are correct, so the answer is (1).

    The trap: these two facts belong to the same page of the chapter but describe unrelated things — a plant cell-wall detail and an animal/coenocytic condition — do not assume a shared topic means a shared error.

    NCERT Class 11 Biology, page 124

20. Q20 Statement I and Statement II

    Statement IRecombination nodules appear during pachytene.

    Statement IICrossing over occurs between non-sister chromatids of homologous chromosomes.

    1. 1.Both Statement I and Statement II are correctCorrect answer
    2. 2.Both Statement I and Statement II are incorrect
    3. 3.Statement I is correct but Statement II is incorrect
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 1 is the answer

    The trap: Both statements are correct.

    What this is testing: two pachytene facts, checked against each other.

    Statement I: recombination nodules appear during pachytene. Correct.
    Statement II: crossing over occurs between non-sister chromatids of homologous chromosomes. Also correct.

    Both are correct, so the answer is (1).

    The trap: these are two halves of the same event — the site (recombination nodules) and the participants (non-sister chromatids) — and having both stated separately can make one feel redundant rather than simply true.

    NCERT Class 11 Biology, page 126

21. Q21 Match the columns

    Match the cell type with its division behaviour:

    Column I	Column II
    (a) Heart cell	(iii) divides by mitosis for repair
    (b) Epidermal cell	(i) divides throughout the life of the plant
    (c) Meristematic cell	(iv) undergoes meiosis to form gametes
    (d) Diploid germ cell	(ii) enters G0, does not divide

    1. 1.(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
    2. 2.(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
    3. 3.(a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)Correct answer
    4. 4.(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)

    Why option 3 is the answer

    The trap: Heart-G0, epidermis-repair mitosis, meristem-lifelong mitosis, germ cell-meiosis.

    What this is testing: matching four cell types to their characteristic division behaviour.

    A heart cell enters G0 and does not divide further; an epidermal cell divides by mitosis for ongoing repair; a meristematic cell divides by mitosis throughout the plant's life; a diploid germ cell undergoes meiosis to form gametes. That gives (a)-(ii), (b)-(iii), (c)-(i), (d)-(iv) — option 3.

    The trap: only the germ cell in this list uses meiosis — the other three all use mitosis for different purposes (arrest, repair, lifelong growth) — do not let 'cell division' in general pull all four towards the same process.

    NCERT Class 11 Biology, page 125

22. Q22 Match the columns

    Match the meiotic prophase I stage with its defining marker:

    Column I	Column II
    (a) Zygotene	(i) terminalisation of chiasmata
    (b) Pachytene	(ii) synaptonemal complex dissolves
    (c) Diplotene	(iii) synaptonemal complex forms
    (d) Diakinesis	(iv) recombination nodules

    1. 1.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
    2. 2.(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)Correct answer
    3. 3.(a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)
    4. 4.(a)-(i), (b)-(iv), (c)-(ii), (d)-(iii)

    Why option 2 is the answer

    The trap: Zygotene-complex forms, Pachytene-recombination nodules, Diplotene-complex dissolves, Diakinesis-terminalisation.

    What this is testing: matching each late prophase I sub-stage to its one defining marker.

    Zygotene is when the synaptonemal complex forms; pachytene shows recombination nodules; diplotene is when that same complex dissolves; diakinesis brings terminalisation of the chiasmata. That gives (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i) — option 2.

    The trap: the synaptonemal complex forms at zygotene and dissolves at diplotene — two stages apart — and a shuffled option can easily attach 'forms' and 'dissolves' to the wrong one of that pair.

    NCERT Class 11 Biology, page 126

23. Q23 Match the columns

    Match the mitotic event with the structure involved:

    Column I	Column II
    (a) Chromosome movement	(iv) kinetochore
    (b) Spindle attachment	(i) spindle fibres
    (c) Chromatid cohesion	(iii) centrosome
    (d) Spindle pole organisation	(ii) centromere

    1. 1.(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
    2. 2.(a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
    3. 3.(a)-(i), (b)-(iv), (c)-(ii), (d)-(iii)Correct answer
    4. 4.(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)

    Why option 3 is the answer

    The trap: Movement-spindle fibres, attachment-kinetochore, cohesion-centromere, poles-centrosome.

    What this is testing: matching each mitotic structure to the specific job it does.

    Chromosome movement is carried out by the spindle fibres; the actual attachment point for the spindle is the kinetochore; the two chromatids stay held together at the centromere; the spindle's poles are organised by the centrosome. That gives (a)-(i), (b)-(iv), (c)-(ii), (d)-(iii) — option 3.

    The trap: kinetochore, centromere and centrosome are three similarly spelled structures with three distinct jobs — attachment site, cohesion point, and pole organiser respectively — and this match is built to see if the names blur together.

    NCERT Class 11 Biology, page 123

24. Q24 Match the columns

    Match the anaphase with what separates:

    Column I	Column II
    (a) Anaphase (mitosis)	(i) nothing separates; bivalents align
    (b) Anaphase I	(ii) sister chromatids
    (c) Anaphase II	(iii) homologous chromosomes
    (d) Metaphase I	(iv) sister chromatids

    1. 1.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)Correct answer
    2. 2.(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)
    3. 3.(a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)
    4. 4.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)

    Why option 1 is the answer

    The trap: Mitotic anaphase and anaphase II-chromatids; anaphase I-homologues; metaphase I-alignment only.

    What this is testing: matching each named anaphase, plus metaphase I, to exactly what separates or does not.

    Ordinary mitotic anaphase and anaphase II both separate sister chromatids; anaphase I separates whole homologous chromosomes instead; metaphase I involves no separation at all — the bivalents are simply aligned. That gives (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i) — option 1.

    The trap: mitotic anaphase and anaphase II look identical in outcome, which is exactly the point — meiosis II mechanically resembles mitosis, and anaphase I is the odd one out in this set.

    NCERT Class 11 Biology, page 127

25. Q25 Exception / incorrect

    All are sub-phases of interphase EXCEPT:

    1. 1.G1 phase
    2. 2.S phase
    3. 3.G2 phase
    4. 4.M phaseCorrect answer

    Why option 4 is the answer

    The trap: The M phase is the division phase, not a sub-phase of interphase.

    What this is testing: what counts as a sub-phase of interphase, and what does not.

    G1, S and G2 are the three sub-phases that make up interphase. The M phase is separate — it is the division phase that follows interphase, not a part of it.

    So the answer is the M phase.

    The trap: G1, S, G2 and M are so often listed together in one sequence that M phase can feel like it belongs to the same set — but interphase specifically means everything before division starts.

    NCERT Class 11 Biology, page 121

26. Q26 Exception / incorrect

    Identify the INCORRECT pairing (division – product):

    1. 1.Mitosis – two diploid cells
    2. 2.Telophase II – dyad of cellsCorrect answer
    3. 3.Meiosis – four haploid cells
    4. 4.Telophase I – dyad of cells

    Why option 2 is the answer

    The trap: Telophase II yields a tetrad of four haploid cells.

    What this is testing: matching each division or stage to its correct cell output, with one pairing deliberately wrong.

    Mitosis gives two diploid cells and meiosis gives four haploid cells — both correct. Telophase I gives a dyad of two cells, correctly listed, but telophase II is wrongly paired with a dyad here — telophase II is the point at which the FINAL tetrad of four haploid cells is produced, not a dyad.

    So the incorrect pairing is 'Telophase II – dyad of cells'.

    The trap: dyad belongs to the end of meiosis I and tetrad to the end of meiosis II — swapping which one comes from which division is the exact error to catch.

    NCERT Class 11 Biology, page 128

27. Q27 Sequence / ordering

    Correct order of the stages of meiosis II:

    1. 1.prophase II → metaphase II → anaphase II → telophase IICorrect answer
    2. 2.metaphase II → prophase II → telophase II → anaphase II
    3. 3.anaphase II → metaphase II → prophase II → telophase II
    4. 4.telophase II → anaphase II → metaphase II → prophase II

    Why option 1 is the answer

    The trap: Prophase II → metaphase II → anaphase II → telophase II.

    What this is testing: the fixed order of the four stages within meiosis II.

    Meiosis II proceeds prophase II, then metaphase II, then anaphase II, then telophase II — the same order mitosis follows, since meiosis II mechanically resembles an ordinary mitotic division. Only option 1 gives that order.

    The trap: because meiosis II looks like mitosis, it is tempting to assume its stage order might differ from mitosis somehow — it does not; both follow the identical P-M-A-T sequence.

    NCERT Class 11 Biology, page 127

28. Q28 NEET 2020

    Cells exit the cell cycle and enter the quiescent stage (G0) at the end of:

    1. 1.S phase
    2. 2.G2 phase
    3. 3.M phase
    4. 4.G1 phaseCorrect answer

    Why option 4 is the answer

    The trap: Cells that will not divide further exit at the end of G1.

    What this is testing: exactly which phase a cell exits when it stops dividing.

    Cells exit the cell cycle at the end of the G1 PHASE to enter the quiescent G0 stage.

    Why the others are wrong: S, G2 and M phases all lie further along the cycle than the point where NCERT places the exit — a cell does not commit to replicating its DNA (S) or preparing for division (G2, M) if it is about to leave the cycle at G1 instead.

    The trap: it can feel more natural for a cell to 'give up' closer to the finish line, at G2 or M, but the branch point NCERT names is earlier, right at the end of G1.

    NCERT Class 11 Biology, page 122

29. Q29 NEET 2016

    During cell growth, DNA synthesis takes place in:

    1. 1.G1-phase
    2. 2.S-phaseCorrect answer
    3. 3.G2-phase
    4. 4.M phase

    Why option 2 is the answer

    The trap: DNA is synthesised during the S-phase.

    What this is testing: which phase of the cycle carries out DNA synthesis.

    DNA synthesis takes place in the S-PHASE.

    Why the others are wrong: G1-phase comes before replication starts, G2-phase comes after it has finished, and the M phase is when the already-replicated DNA is distributed to daughter cells, not synthesised.

    The trap: G1 and G2 both flank the S phase and can feel equally 'active' with DNA, but only the middle phase actually makes new DNA.

    NCERT Class 11 Biology, page 121

30. Q30 NEET 2013

    The aleurone cells of a plant with 42 chromosomes in the root tip carry:

    1. 1.63 chromosomesCorrect answer
    2. 2.21 chromosomes
    3. 3.42 chromosomes
    4. 4.84 chromosomes

    Why option 1 is the answer

    The trap: Aleurone tissue is triploid (3n); with 2n=42, 3n=63.

    What this is testing: the ploidy of the aleurone layer relative to the plant's own root-tip chromosome number.

    With 42 chromosomes in the diploid (2n) root tip, the aleurone tissue is triploid (3n), giving 63 CHROMOSOMES.

    Why the others are wrong: 21 would be the haploid (n) number, half of 42; 42 itself is just the ordinary diploid count, not the aleurone's; 84 would be double the diploid number (4n), which overshoots the triploid value asked for.

    The trap: it is easy to reach for a simple doubling or halving of 42, but the aleurone's defining feature is being triploid, exactly one and a half times the diploid number — 63, not 84 or 21.

    NCERT Class 11 Biology, page 125