Q.Compare endosperm and perisperm. Describe the development of endosperm.

Showing the 12 most recent of 21 on this concept.

1. CBSE 2026Set A1 markMCQ
   Q.Which cell of the embryo sac becomes primary endosperm cell after triple fusion?

   (a) Central cell

   (b) Synergids

   (c) Antipodals

   (d) Egg cell

   ›Reveal solutionSolution

   One male gamete fuses with the two polar nuclei of the central cell (triple fusion), turning the central cell into the primary endosperm cell.

   In double fertilisation, one male gamete fuses with the egg (syngamy) to form the zygote. The second male gamete fuses with the two polar nuclei present in the central cell — this is triple fusion, producing a triploid primary endosperm nucleus (PEN). Because this fusion occurs in the central cel …

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2. CBSE 2026Set ANNUAL1 markMCQ
   Q.The cells of endosperm of a plant have 27 chromosomes. What will be the number of chromosomes in its gametes?

   (a) 18

   (b) 9

   (c) 36

   (d) 27

   ›Reveal solutionSolution

   Endosperm in angiosperms is triploid (3n); dividing its chromosome number by 3 gives the haploid number found in the plant's gametes.

   In flowering plants, double fertilisation produces two products: the diploid (2n) zygote from fusion of the egg and one male gamete, and the triploid (3n) primary endosperm nucleus from fusion of the two polar nuclei (which together are 2n) with the second male gamete (n).

   Given the endosperm has 27 chromosomes: 3n = 27, so n = 27 / 3 = 9.

   …

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3. CBSE 2025Set ANNUAL1 markMCQ
   Q.What is the ploidy of endosperm in flowering plants ?

   (a) 2n

   (b) 3n

   (c) 4n

   (d) 6n

   ›Reveal solutionSolution

   Triple fusion during double fertilisation makes the endosperm 3n.

   In flowering plants, double fertilisation involves two fusion events inside the embryo sac. One male gamete (n) fuses with the egg cell (n) to form the diploid (2n) zygote (syngamy). The second male gamete (n) fuses with the diploid (2n) secondary nucleus — itself formed by fusion of the two polar nuclei — to form the primary endosperm nucleus (PEN). Since this event involves the fusion of three haploid nuclei (one male gamete + two …

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4. CBSE 2024Set D1 markMCQ
   Q.How many chromosomes are present in endosperm (Angiosperm)?

   (a) n (Haploid)

   (b) 2n (Diploid)

   (c) 3n (Triploid)

   (d) 4n (Tetraploid)

   ›Reveal solutionSolution

   The endosperm of angiosperms is triploid (3n), formed by the fusion of one male gamete with the two haploid polar nuclei of the central cell.

   In angiosperms, double fertilisation occurs inside the embryo sac. One of the two male gametes (n) delivered by the pollen tube fuses with the egg cell (n) to form the diploid zygote (2n), which develops into the embryo. This is called syngamy.

   …

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5. CBSE 2024Set BOTANY1 mark
   Q.Correct the statement, if necessary, by changing the underlined word(s) only: Primary endosperm nucleus is produced by double fertilization.

   ›Reveal solutionSolution

   Strictly, the PEN arises from triple fusion, not from double fertilization as a whole.

   In angiosperms, one pollen tube delivers two male gametes into the embryo sac. One male gamete fuses with the egg cell (syngamy) to form the diploid zygote. The other male gamete fuses with the two polar nuclei (or the secondary nucleus formed by their fusion) located in the central cell — this second event is called triple fusion because three haploid nuclei (one male gamete + two polar nuclei) are involved, and it produces the triploid (3n) Primary Endosperm Nucleus (PEN), which develops into the endosperm. Since both syngamy and …

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6. CBSE 2024Set ANNUAL1 mark
   Q.The central cell after triple fusion becomes the ________.

   ›Reveal solutionSolution

   The central cell after triple fusion becomes the primary endosperm cell (PEC); the triploid nucleus inside it is the primary endosperm nucleus (PEN).

   During double fertilisation in flowering plants, one male gamete fuses with the egg to form the diploid zygote (syngamy), while the second male gamete fuses with the two polar nuclei of the central cell — this is triple fusion, involving three haploid nuclei (one male gamete + two polar nuclei). The triploid (3n) nucleus produced is the primary endosperm nucleus (PEN). The central cell that contained the polar nuclei is now called the **primary endosperm cell ( …

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7. CBSE 2023Set ANNUAL1 markMCQ
   Q.Double fertilization occurs in -

   (a) Algae

   (b) Bryophytes

   (c) Gymnosperms

   (d) Angiosperms

   ›Reveal solutionSolution

   Double fertilization — a defining feature of flowering plants — occurs only in angiosperms.

   Double fertilization involves two fusion events inside the embryo sac: syngamy, in which one male gamete fuses with the egg cell to form the diploid zygote, and triple fusion, in which the second male gamete fuses with the two polar nuclei to form the triploid primary endosperm nucleus (PEN). Both …

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8. CBSE 2023Set ANNUAL1 markMCQ
   Q.The primary endosperm nucleus formed in angiosperms is

   (a) haploid

   (b) diploid

   (c) triploid

   (d) tetraploid

   ›Reveal solutionSolution

   Triple fusion (one sperm + two polar nuclei) produces the primary endosperm nucleus, which is triploid — this is unique to angiosperms.

   In angiosperms, double fertilisation occurs inside the embryo sac: one male gamete (n) fuses with the egg cell (n) to form the diploid (2n) zygote (syngamy), and the second male gamete (n) fuses with the two polar nuclei (each n) located in the central cell, in a process called triple fusion. This produces the …

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9. CBSE 2023Set ANNUAL1 markMCQ
   Q.In angiosperms, triple fusion is required for the formation of

   (a) embryo

   (b) endosperm

   (c) fruit

   (d) seed

   ›Reveal solutionSolution

   Triple fusion, in which one male gamete fuses with the two polar nuclei of the central cell, produces the triploid primary endosperm nucleus that develops into the nutritive endosperm tissue.

   In double fertilization, one of the two male gametes delivered by the pollen tube fuses with the two polar nuclei located in the central cell of the embryo sac — since three haploid nuclei are involved in this single fusion event, it is called triple fusion. The resulting triploid (3n) nucleus is the primary endosperm nucleus (PEN), which divides repe …

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10. CBSE 2023Set ANNUAL1 markMCQ
    Q.Which of the following is an example of free nuclear endosperm?

    (a) Coconut water

    (b) Castor

    (c) Sugarcane juice

    (d) Groundnut

    ›Reveal solutionSolution

    Free-nuclear endosperm forms many nuclei without immediate cell-wall formation; coconut "water" is liquid free-nuclear endosperm.

    Endosperm development begins with repeated divisions of the primary endosperm nucleus (PEN, formed by triple fusion). In the more common type, free nuclear endosperm, the nucleus divides repeatedly, but no cell wall is laid down around the resulting nuclei for some time, so numerous free (naked) nuclei remain suspended in the common cytoplasm; only later does cellularisation usually occur towards the periphery. The liquid endosperm of a tender coconut (the "coconut water") is a well-known example of persistent free-nuc …

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11. CBSE 2023Set ANNUAL1 markMCQ
    Q.What is the ploidy of the chromosomes in the endosperm of angiosperm plants?

    (a) n

    (b) 3n

    (c) 2n

    (d) both

    (a) and (b)

    ›Reveal solutionSolution

    Angiosperm endosperm is triploid (3n).

    In double fertilisation of angiosperms, one male gamete (n) fuses with the egg to form the diploid (2n) zygote, and the second male gamete (n) fuses with the two polar nuclei (n + n) of the central cell. This triple fusion produces t …

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12. CBSE 2022Set ANNUAL1 markMCQ
    Q.Double fertilization occurs in -

    (a) Algae

    (b) Bryophyta

    (c) Gymnospermic Plants

    (d) Angiospermic Plants

    ›Reveal solutionSolution

    Double fertilization is unique to flowering plants (angiosperms).

    In double fertilization, one of the two male gametes delivered by the pollen tube fuses with the egg cell (syngamy) to form the diploid zygote, while the second male gamete fuses with the two polar nuclei (or the secondary nucleus) of the central cell to form the triploid primary endosperm nucleus (triple fusion). Because it involves both syngamy and tr …

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