Solutions of How do Organisms Reproduce? Lakhmir Singh Manjit Kaur LAQ, and MCQ Pg No. 142 Class 10 Biology
34A. What is meant by reproduction?
Answer
→ The process by which living beings produce its own like is called reproduction.
34B. What are the two general methods of reproduction in organisms?
Answer
→ There are two methods of reproduction:
(i) Sexual reproduction (ii) Asexual Reproduction
34C. How does an Amoeba reproduce ? Describe the process of reproduction in Amoeba with the help of labelled diagrams of different stages in its reproduction process.
Answer
→ Amoeba reproduces by common asexual method called binary fission. In this method, Amoeba cell divides into two equal daughter cells. The nucleus of amoeba first divides into two parts. After that the cytoplasm of amoeba divides into two parts, one part around each nucleus. This leads to the formation of the two daughter Amoebae cell having a nucleus and its own cell organelles.
34D. What is the name of the process by which Amoeba reproduces ?
Answer
→ Amoeba reproduces by binary fission.
34E. Name two organisms which reproduce by the same asexual process as that of Amoeba.
Answer
→ Paramecium and Leishmania reproduce by binary fission.
35A. What is the difference between the two asexual methods of reproduction : fission and fragmentation?
Answer
→ Differences between the fission and fragmentation:
Fission
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Fragmentation
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It is a process in which an organism splits to form two or more new organisms.
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It is a process in which the body breaks up into two or more pieces on maturing, each of which subsequently grows to form a complete new organism.
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It occurs in unicellular organisms.
Example: Amoeba.
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It occurs in multicellular organisms.
Example: Spirogyra.
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35B. Name one organism which reproduces by fission and another which reproduces by fragmentation.
Answer
→ Fission: Amoeba; Fragmentation: Spirogyra.
35C. What is meant by multiple fission ? Name one organism which reproduces by the process of multiple fission.
Answer
→ Division of single-celled organism into many daughter cells simultaneously is called multiple fission. Plasmodium reproduces by multiple fission.
35D. Describe the process of reproduction in Hydra with the help of labelled diagrams. What is the name of this process of reproduction ?
Answer
→ Hydra reproduces by budding. In hydra, a bud develops as an outgrowth due to repeated cell divisions at one specific site. This bud then grows gradually to form a small hydra by developing a mouth and tentacles. The tiny new hydra detaches itself from the parent body and become new independent individual.
35E. Name one unicellular organism which reproduces by the same asexual process as Hydra.
Answer
→ Yeast reproduces by buding.
36A. Name the method by which bread mould (Rhizopus fungus) reproduces. Is this method sexual or asexual ?
Answer
→ Rhizopus fungus (bread mould) reproduces by spore formation. It is asexual method of reproduction.
36B. What is yeast? Describe the process of reproduction in yeast with the help of labelled diagrams.
Answer
→ Yeast is a tiny, unicellular non-green plant which reproduces by an asexual method called budding.
In yeast, first a bud appears on the outside of the cell wall. The nucleus of the parent cell divides into two parts and one part of the nucleus moves into the bud. Ultimately, the bud separates off from the parent cell and forms a new yeast cell.
36C. Name a tiny fresh-water animal which reproduces by the same method as that of yeast ? What is this method known as ?
Answer
→ Hydra is a tiny fresh water animal which also reproduces by budding.
36D. Name two marine organisms which also reproduce by the same method as yeast but form colonies.
Answer
→ Corals and sponge are two marine organisms which also reproduce by the same method as yeast but form colonies.
37A. What is meant by 'grafting' as a means of propagation in plants?
Answer
→ Grafting - It is a method of artificial propagation in which the cut stems of two different plants (one with roots and other without roots) are joined together in such a way that the stems join and grow as a single plant.
37B. Define 'stock' and 'scion'.
Answer
→ The cut stem of a plant having roots (and fixed in soil) is called stock and the cut stem of another plant (without roots) is called scion.
37C. Describe the grafting method for the artificial propagation of plants with the help of labelled diagrams.
Answer
→ In grafting method, two plants are chosen which are used as scion and stock. First the stem (or branch) is cut from the plant chosen to be made scion by giving a slanting cut. The stem of second plant is also in a slanting way. The lower part of this plant is stock. The scion is placed over the stock and is fitted together by binding tightly by a piece of cloth or plastic sheet. The cut soon heals and the stock and scion of two plants grow together to become one plant.
37D. Name two fruit trees which are usually propagated by grafting method.
Answer
→ Apple and oranges are propagated by grafting method.
37E. State two advantages of grafting method of artificial propagation of plants.
Answer
→ Advantages of grafting method:
(i) It can be used to produce varieties of seedless fruits.
(ii) It enables us to combine the most desirable characteristics of the two plants in its flowers and fruits.
37F. What is the difference between the cuttings method and grafting method for the artificial propagation of plants?
Answer
→ Difference between the cuttings method and grafting method:
Cutting Method
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Grafting Method
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In this method, a small part of the plant is removed by making a cut with a sharp knife.
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In this method, the cut stems of two different plants (one with roots and other without roots) are joined together in such a way that the stems join and grow as a single plant.
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The new plant formed is exactly similar to the parent plant.
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The new plant produced has the characteristics of both the parent plants.
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38A. What is tissue culture?
Answer
→ Tissue culture is a technique of artificial propagation of plant. It is done by taking a small piece of plant tissue (or cells) removed from the growing tips of a plant and grow it in suitable growth medium.
38B. Name any four types of ornamental plants which are being produced by tissue culture technique.
Answer
→ Orchids, dahlia, carnation and chrysanthemum are produced by tissue culture technique.
38C. What is the importance of DNA copying in reproduction? Explain with an example.
Answer
→ The chromosomes are located in the nucleus of a cell and they contain information for the inheritance of traits from the parents to the next generation in the form of DNA molecules so the characteristics of a parent organism are transmitted to their off springs. DNA is the information source for making proteins. If information is different, different protein will be made that lead to altered body design.
Example: Offspring's produced by asexual reproduction have slight variations from their parents.
38D. How does reproduction help in providing stability to populations of species ?
Answer
→ Individual organisms of a species get some variations by the process of reproduction which makes them survive adverse environmental conditions (heat, cold etc.). Thus, variations during reproduction gives stability to a species.
38E. Why is variation during reproduction beneficial to the species but not necessarily for the individual?
Answer
→ Variation is useful for the survival of species than individuals because sometimes for a species, the environmental conditions change so drastically that their survival becomes difficult. If all the organisms of a population are living in a particular habitat, then there is a danger that all of them may die and no one would survive under drastic conditions. Only few variants which are resistant to these drastic changes would be able to survive. However, if these variants were not there, then the entire species of that organism would have been destroyed. Thus, variation is useful to species but not the individual.
39A. What is a 'cutting' in respect of plants for propagation purposes?
Answer
→ In this method, a small part of the plant is removed by making a cut with a sharp knife.
39B. What care should be taken while making a cutting from a plant?
Answer
→ While cutting, care should be taken to see that there are some buds on it.
39C. Describe the cuttings method for the artificial propagation of plants. illustrate your answer with the help of labelled diagrams.
Answer
→ In this method, a parent plant is cut in a way that the cut part has buds and the lower part is buried in the moist soil. After a couple of days, the cut part develops roots and shoot and a new similar plant grows.
39D. Name any two plants which are usually propagated by the cuttings method.
Answer
→ Rose and Bougainvillea are propagated by cutting method.
Multiple Choice Questions (MCQs)-Pg-143
40. Asexual reproduction is :
A. a fusion of specialised cells
B. a method by which all types of organisms reproduce
C. a method producing genetically identical offspring
D. a method in which more than one parent are involved
Answer
→ In asexual reproduction, only single parent is involved. It is primitive type of reproduction. Off springs are the identical copies of the parent.
41. One of the following organisms does not reproduce by binary fission. This is:
A. Amoeba
B. Plasmodium
C. Leishmania
D. Paramecium
Answer
→ Amoeba, Leishmania and paramecium reproduce by binary fission whereas plasmodium reproduces by multiple fission.
42. The micro-organism which reproduces by multiple fission is the one which causes the disease known as:
A. Kala-azar B. marasmus
C. malaria D. amoebiasis
Answer
→ Plasmodium reproduces by multiple fission and cause malaria disease in humans.
43. The protozoan having a flagellum at its one end is :
A. Amoeba B. Paramecium
C. Hydra D. Leishmania
Answer
→ Leishmania is a protozoan which have a flagellum at its one end.
44. In the list of organisms given below, those which reproduce by the asexual method are:
(i) banana (ii) yak
(iii) yeast (iv) Amoeba
A. (ii) and (iv)
B. (i), (iii) and (iv)
C. (i) and (iv)
D. (ii), (iii) and (iv)
Answer
→ Banana, yeast and amoeba reproduce by asexually. Banana reproduce by vegetative propagation; yeast reproduces by budding and; Amoeba reproduces by binary fission.
45. One of the following organisms does not reproduce by budding . This is :
A. Sponge B. Yeast
C. Hydra D. Planaria
Answer
→ Sponge, yeast and hydra reproduce by budding whereas planaria reproduces by regeneration.
46. The disease kala-azar is caused by a micro-organism known as :
A. Planaria B. Leech
C. Leishmania D. Plasmodium
Answer
→ Leishmania is a micro-organism which causes a disease called kala-azar.
47. Reproduction is essential for living organisms in order to :
A. keep the individual organ alive
B. fulfil their energy requirements
C. maintain growth
D. continue the species for ever
Answer
→ Reproduction is one of the important characteristics of living things. The ability of organism to produce young ones of its own kind is called reproduction. It is essential for the continuity of species.
48. The unicellular organism which reproduces by budding is :
A. Spirogyra B. Hydra
C. Planaria D. Yeast
Answer
→ Yeast is a unicellular organism which reproduces by budding. Spirogyra reproduces by fragmentation; planaria reproduces by regeneration and; hydra (a multicellular organism) reproduces by budding.
49. A multicellular organism which reproduces by budding is :
A. Amoeba B. Yeast
C. Leishmania D. Hydra
Answer
→ Hydra is a multicellular organism which reproduces by budding whereas Yeast is a unicellular organism reproduces by budding.
50. The off springs formed by asexual reproduction method have greater similarity among themselves because :
(i) asexual reproduction involves only one parent
(ii) asexual reproduction involves two parents
(iii) asexual reproduction involves gametes
(iv) asexual reproduction does not involve gametes
A. (i) and (ii) B. (i) and (iii)
C. (ii) and (iv) D. (i) and (iv)
Answer
→ The off springs formed by asexual reproduction method have greater similarity among themselves because in asexual reproduction, only one parent is involved without forming gametes.
51. A simple multicellular animal having tentacles which lives in freshwater usually reproduces by the asexual process of:
A. binary fission B. spore formation
C. budding D. fragmentation
Answer
→ A simple multicellular animal (Hydra) having tentacles which lives in freshwater usually reproduces by the asexual process of budding.
52. One of the following does not reproduce by spore formation method. This is:
A. Rhizopus fungus
B. Penicillium fungus
C. Yeast fungus
D. Mucor fungus
Answer
→ Rhizopus, penicillium and mucor fungus reproduce by spore formation method whereas yeast reproduces by budding.
53. The factors responsible for the rapid spreading of bread mould on slices of bread are :
(i) presence of large number of spores in air
(ii) presence of large number of thread-like branched hyphae
(iil) presence of moisture and nutrients
(iv) formation of round shaped sporangia
A. (i) and (iii) B. (ii) and (iv)
C. (i) and (ii) D. (iii) and (iv)
Answer
→ The factors responsible for the rapid growth of bread mould on slices of bread are presence of large number of spores in air as well as presence of moisture and nutrients on the slice of bread.
54. One of the following reproduces by forming spores. This in :
A. Fern B. Planaria
C. Spirogyra D. Potato
Answer
→ Fern reproduces by forming spores.
55. Asexual reproduction through budding takes place in:
(i) Amoeba and Yeast
(ii) Yeast and Hydra
(iii) Hydra and Plasmodium
(iv) Corals and Sponges
A. (i) and (ii) B. only (ii)
C. (i) and (iii) D. (ii) and (iv)
Answer
→ Hydra and yeast reproduce by budding. Coral and sponges are two marine organism which also reproduce by budding.
56. A feature of reproduction that is common to Amoeba, Yeast and Bacterium is that:
A. they are all multicellular
B. they are all unicellular
C. they reproduce only sexually
D. they reproduce asexually
Answer
→ Amoeba, yeast and bacterium reproduce by asexually. Amoeba reproduce by binary fission, yeast reproduces by budding and bacterium reproduces by multiple fission.
57. One of the following organisms does not reproduce by fission. This is :
A. Amoeba B. Leishmania
C. Planaria D. Plasmodium
Answer
→ Simple organisms like hydra and planaria are capable of producing new individual through the process of regeneration.
58. An organism which may be considered to be a kind of plant and reproduces by budding is :
A. Paramecium B. Bread mould
C. Hydra D. Yeast
Answer
→ Yeast is a unicellular organism which may be considered to be a kind of a plant and reproduces by budding.
59. An animal which reproduces by the process of budding is :
A. Plasmodium B. yeast
C. Hydra D. Planaria
Answer
→ Hydra is a multicellular organism which reproduces by budding.
60. In Spirogyra, asexual reproduction takes place by :
A. division of a cell into two cells
B. breaking up of filaments into smaller bits
C. division of a cell into many cells
D. formation of a large number of buds
Answer
→ In spirogyra algae, the plant body breaks up into smaller fragments. Each fragment grows into a new individual.
61. The ability of a cell to divide into several cells during reproduction in Plasmodium is called :
A. budding
B. fragmentation
C. binary fission
D. multiple fission
Answer
→ The ability of a cell to divide into several cells during reproduction in Plasmodium is called multiple fission.
62. In Rhizopus fungus, the fine thread-like structures spread on the whole surface of slice of bread are called :
A. rhizoids
B. stems
C. roots
D. hyphae
Answer
→ In Rhizopus fungus, the fine thread-like structures spread on the whole surface of slice of bread are called hyphae.
63. Vegetative propagation refers to the formation of new plants from the following existing organs of the old plants:
A. stems, roots and flowers
B. stems, roots and leaves
C. stems, flowers and fruits
D. stems, leaves and flowers
Answer
→ Vegetative propagation is the method of asexual reproduction in which new plants are produced from the vegetative parts of the plant like stems, roots and leaves.
64. The two organisms which can regenerate fully from their cut body parts are :
A. Paramecium and Hydra
B. Hydra and Amoeba
C. Planaria and Leishmania
D. Hydra and Planaria
Answer
→ Planaria and Leishmania are two organisms which can regenerate fully from their cut body parts.
65. The two types of organisms which produce colonies by the process of budding are :
A. Hydra and Corals
B. Yeast and Sponges
C. Corals and Sponges
D. Hydra and Yeast
Answer
→ Corals and Sponges are two organisms which reproduce by budding and form colonies.
66. Spore formation is the most common asexual method of reproduction in :
A. protozoa
B. tubers
C. fungi
D. algae
Answer
→ Bread mould (a fungus) reproduces by the asexual method called spore formation.
67. An alga which reproduces by the asexual reproduction method called fragmentation is:
A. Rhizopus
B. Salmonella
C. Plasmodium
D. Spirogyra
Answer
→ Spirogyra an alga which reproduces by the asexual reproduction method called fragmentation.
68. The organisms which can reproduce by fragmentation are :
A. Corals and Sponges
B. Corals and Spirogyra
C. Sea anemone and Spirogyra
D. Sponges and Sea anemones
Answer
Sea anemone and Spirogyra reproduce by the asexual method called fragmentation.
69. Binary fission describes the type of reproduction where the organism divides to form:
A. many spores
B. two daughters
C. many buds
D. two hyphae
Answer
→ In binary fission, organism cell divides into two equal daughter cells. The nucleus of organism first divides into two parts. After that the cytoplasm divides into two parts, one part around each nucleus. This leads to the formation of the two daughter cells having a nucleus and its own cell organelles.
70. The cut part of a plant stem (without roots) which is used in grafting is called :
A. stock
B. stump
C. scion
D. graft
Answer
→ The cut part of a plant stem (without roots) which is used in grafting is called scion.
71. The cut part of plant stem (having roots and fixed to ground) which is used in the process of grafting is known as:
A. stock
B. scion
C. cutting
D. bud
Answer
→ The cut part of plant stem (having roots and fixed to ground) which is used in the process of grafting is known as stock.
72. Multiple fission occurs in one of the following. This is :
A. bread mould
B. kala-azar parasite
C. flatworm
D. malaria parasite
Answer
→ Plasmodium which causes malaria reproduces by multiple fission.
73. An organism having a whip-like structure at one end which reproduces by the process of binary fission is:
A. Hydra
B. Paramecium
C. Leishmania
D. Plasmodium
Answer
→ Leishmania have a whip-like structure at one end and reproduces by the process of binary fission.
74. A tiny animal having tentacles which reproduces by growing buds on the sides of its body is :
A. Planaria
B. Yeast
C. Amoeba
D. Hydra
Answer
→ Hydra reproduces by budding. In hydra, a bud develops as an outgrowth due to repeated cell divisions at one specific site. This bud then grows gradually to form a small hydra by developing a mouth and tentacles. The tiny new hydra detaches itself from the parent body and become new independent individual.
75. An organism which can reproduce by two asexual reproduction methods one similar to the reproduction in yeast and the other similar to the reproduction in Planaria is :
A. Spirogyra
B. Bryophyllum
C. Hydra
D. Sea anemone
Answer
→ Hydra reproduces by two asexual reproduction methods. One is budding similar to the reproduction in yeast and the other is regeneration similar to the reproduction in Planaria.
76. Stock and scion are involved in the artificial propagation method known as :
A. tissue culture
B. layering
C. grafting
D. cuttings
Answer
→ Grafting is a method of artificial propagation in which the cut stems of two different plants (one with roots and other without roots) are joined together in such a way that the stems join and grow as a single plant. The cut stem of a plant having roots (and fixed in soil) is called stock and the cut stem of another plant (without roots) is called scion.
77. In asexual reproduction, two offsprings having the same genetic material and the same body features are called:
A. callus
B. twins
C. clones
D. chromosomes
Answer
→ In asexual reproduction, two offsprings having the same genetic material and the same body features are called clones.
78. The method of asexual reproduction in plants in which callus is produced is :
A. Micropropagation
B. vegetative propagation
C. regeneration
D. fragmentation
Answer
→ The method of asexual reproduction in plants in which callus is produced is micropropagation.
79. A Planaria worm is cut horizontally in the middle into two halves P and Q such that the part P contains the whole head of the worm. Another Planaria worm is cut vertically into two• halves R and S in such a way that both the cut pieces R and S contain half head each. Which of the cut pieces of the two Planaria worms could regenerate to form the complete respective worms ?
A. only P
B. only R and S
C. P, Rand S
D. P, Q, R and S
Answer
→ If the body of planaria is cut into any number of pieces, each piece grows into a complete organism through the process of regeneration.