Class 10 Science · Chapter 7

How do Organisms Reproduce?

434 Class 10 Science questions on How do Organisms Reproduce? from the NCERT textbook, NCERT Exemplar and CBSE board papers 2017–2026, each with its answer and a step-by-step solution.

CBSE Class 10 Science previous year papers, with answers →

Questions · page 22 of 22

1. Q421 CBSE 2017
   To perform an experiment ​to identify ​the different parts of an embryo of a dicot seed, first of all you ​require a dicot seed. Select dicot seeds from the following ​group : Wheat, ​Gram, Maize, ​Pea, Barley, ​Ground-nut

   1. (a)Wheat, Gram and Pea
   2. (b)Gram, Pea and Ground-nut
   3. (c)Maize, Pea and Barley
   4. (d)Gram, Maize and Ground-nut
   Show answer

   (b) Gram, Pea and Ground-nut

   Step-by-step solution →
2. Q422 CBSE 2017
   Select from the ​following a group ​of ​seeds, whose any ​seed ​may be used to ​study the embryo of ​a ​dicot seed.

   1. (a)Ground-nut, Kidney bean, Pea
   2. (b)Gram, Pea, Maize
   3. (c)Maize, Wheat, Kidney bean
   4. (d)Gram, Wheat, Ground-nut
   Show answer

   (a) Ground-nut, Kidney bean, Pea

   Step-by-step solution →
3. Q423 CBSE 2017
   Consider some steps given below about the experiment on studying an embryo of a gram seed and ​select the correct sequence ​: I. ​Drain the excess water, cover the seeds with a wet cloth and leave them as ​it is for ​a day. II. Soak the seeds in plain water ​and keep them overnight. III. ​Cut open the soaked seed and observe ​its different parts. IV. Take some healthy seeds in a petridish.

   1. (a)II, I, III, IV
   2. (b)IV, I, II, III
   3. (c)IV, III, I, II
   4. (d)IV, II, I, III
   Show answer

   (d) IV, II, I, III

   Step-by-step solution →
4. Q424 CBSE 2017
   The sketch of ​a dicotyledonous seed is shown below. The ​correct ​labelling for parts A, B, ​C ​and ​D in proper ​sequence is

   1. (a)radicle, plumule, cotyledon, seed coat.
   2. (b)radicle, plumule, seed coat, cotyledon.
   3. (c)plumule, radicle, cotyledon, seed coat.
   4. (d)plumule, radicle, seed coat, cotyledon
   Show answer

   (d) plumule, radicle, seed coat, cotyledon

   Step-by-step solution →
5. Q425 CBSE 2017
   On ​observing an embryo of ​a pea seed, a student listed its various parts ​as ​given below : Micropyle, Cotyledon, Plumule, Testa, Radicle, Tegmen On examining the list the teacher ​remarked that ​out of ​these only three parts belong to ​embryo. Select these three parts :

   1. (a)Testa, Radicle, Cotyledon
   2. (b)Tegmen, Radicle, Micropyle
   3. (c)Cotyledon, Plumule, Radicle
   4. (d)Cotyledon, Plumule, Testa
   Show answer

   (c) Cotyledon, Plumule, Radicle

   Step-by-step solution →
6. Q426 CBSE 2017
   In the following figure different ​stages ​of ​binary fission in Amoeba are depicted, which are ​not ​in proper sequence ​: The correct sequence is ​:

   1. (a)II, III, IV, I
   2. (b)I, II, IV, III
   3. (c)III, IV, II, I
   4. (d)I, III, IV, II
   Show answer

   (a) II, III, IV, I

   Step-by-step solution →
7. Q427 CBSE 2017
   In which of ​the following ​figures is budding Not ​shown ​?

   1. (a)A
   2. (b)B
   3. (c)C
   4. (d)D
   Show answer

   (c) C

   Step-by-step solution →
8. Q428 CBSE 2017
   A student is given a permanent slide showing binary ​fission in Amoeba. ​Write two steps to focus ​the slide under microscope. ​Draw diagram and label the parts.
   Show answer

   Clip the slide on the stage, focus under low power with the coarse knob, then high power with the fine knob.

   Steps to focus: (1) Place the slide on the stage with the specimen over the centre of the stage opening, hold it with the clips and adjust the mirror so that the field is well lit. (2) With the low-power objective, bring the Amoeba into focus with the coarse adjustment knob; then switch to the high-power objective and make the image sharp with the fine adjustment knob. Diagram: binary fission in Amoeba (see the figure), drawn as (a) the parent Amoeba, labelled nucleus, cytoplasm, plasma membrane, pseudopodium and contractile vacuole; (b) the nucleus dividing; (c) the cytoplasm constricting; (d) two daughter Amoebae, each with a nucleus.

   Step-by-step solution →
9. Q429 CBSE 2017
   Name the type of asexual ​reproduction in which two ​individuals are ​formed from ​a single ​parent and the parental identity is lost. Write the first step from where such ​a ​type of reproduction begins. Draw first ​two stages of this reproduction.
   Show answer

   It is binary fission; its first step is the elongation of the cell and nucleus, and the nucleus then divides into two.

   Binary fission (for example, in Amoeba). The first step is the elongation of the cell and its nucleus: after the DNA is copied, the nucleus lengthens and then splits into two (karyokinesis), and only then does the cytoplasm divide (cytokinesis). First two stages: (1) the parent cell lengthening, with its nucleus elongated and dividing into two; (2) the lengthened cell with two nuclei and its cytoplasm beginning to constrict in the middle (see the figure).

   Step-by-step solution →
10. Q430 CBSE 2017
    You have to perform the ​experiment, ​“To identify ​the ​different parts of an embryo ​of a gram seed.” Describe the procedure ​that you would follow.
    Show answer

    Soak gram seeds, remove the seed coat, separate the cotyledons and identify the plumule and radicle with a hand lens.

    1. Soak a few gram seeds in water overnight; drain them and keep them covered with a wet cloth for about a day so that they stay moist. 2. Take a soaked seed and gently remove its seed coat. 3. Carefully separate the two cotyledons without damaging the embryo attached between them. 4. Observe with a hand lens and identify the cotyledons (food store), the plumule (future shoot) and the radicle (future root); draw a labelled diagram.

    Step-by-step solution →
11. Q431 CBSE 2017
    Draw in sequence (showing ​the ​four ​stages), the ​process ​of binary fission in ​Amoeba.
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    Parent Amoeba, nucleus divides, cytoplasm constricts, then two daughter Amoebae separate: the four stages of binary fission.

    The four stages, in order (see the drawing): 1. the parent Amoeba with one nucleus; 2. the nucleus elongates and divides into two; 3. the cytoplasm constricts between the two nuclei; 4. the constriction completes and two daughter Amoebae separate, each with its own nucleus.

    Step-by-step solution →
12. Q432 CBSE 2017
    Draw ​a labelled ​diagram to ​show ​that particular stage of binary ​fission in Amoeba in which its nucleus elongates and ​a constriction appears in its ​cell membrane.
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    The diagram shows an Amoeba with one elongated nucleus lying across the middle and a shallow constriction pinching the cell membrane.

    The labelled diagram shows Amoeba with a single elongated nucleus lying across the middle of the cell and a shallow constriction pinching the cell membrane in at the middle, above and below it. Labels: cell (plasma) membrane, cytoplasm, elongated nucleus, constriction in the cell membrane, pseudopodium.

    Step-by-step solution →
13. Q433 CBSE 2017
    Explain the process of ​budding in yeast by ​drawing ​labelled diagrams of different ​stages ​of ​the process in ​a correct sequence.
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    In yeast, a bud grows on the parent cell, receives a daughter nucleus, and separates as a new cell or forms a chain.

    Budding in yeast (asexual reproduction), in sequence: (1) A parent yeast cell has one nucleus. (2) A small outgrowth, the bud, appears on one side of the parent. (3) The nucleus divides into two, and one daughter nucleus moves into the bud. (4) The bud grows and the neck joining it to the parent narrows. (5) The bud separates as a new yeast cell; buds may also stay attached and bud again, forming a chain of buds. The labelled diagrams (parent cell, nucleus, bud, daughter nucleus, new yeast cell, chain of buds) are in the figure.

    Step-by-step solution →
14. Q434 CBSE 2017
    Draw ​a diagram showing ​different ​parts of an embryo ​of gram ​seed ​and label them.
    Show answer

    The gram embryo has two cotyledons, which store food, with the plumule (future shoot) and radicle (future root) on a short embryonal axis.

    Labelled diagram (see the figure). The embryo of a gram seed consists of: (i) two cotyledons, which store food; (ii) the plumule, the future shoot; (iii) the radicle, the future root. The plumule and the radicle lie at the two ends of a short embryonal axis to which the cotyledons are attached.

    Step-by-step solution →