Solutions of How do Organisms Reproduce? Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 141 Class 10 Biology
1. Which life process ensures that a plant or animal species will not disappear from this earth?
Answer
→ Reproduction is an important life process which ensures that a plant or animal species does not disappear from this earth.
2. What is the name of the reproductive process :
(a) which involves two parents?
(b) which involves only one parent ?
Answer
→ (a) In sexual reproduction, two parents are involved.
(b) In asexual reproduction, only one parent is involved.
3. State whether the following statement is true or false :
Spores produced by the bread mould plant are actually its seeds.
Answer
→ This statement is false because spores produced by the bread mould plant are not its seeds.
4. Most of the plants reproduce by sexual method. Name two plants which can reproduce asexually.
Answer
→ Hydra and plasmodium reproduce by asexually.
5. Which type of reproduction:
(a) involves gametes ?
(b) does not involve gametes ?
Answer
→ (a) Sexual reproduction involves gametes.
(b) Asexual reproduction does not involve gametes.
6. State whether human beings reproduce by sexual method or asexual method.
Answer
→ Human beings reproduce by sexual method.
7A. Name two animals which reproduce sexually.
Answer
→ Cows and dogs are reproduce sexually.
7B. Name two animals which reproduce asexually.
Answer
→ Hydra and planaria reproduce by asexually.
8. Name one organism which reproduces by spore formation.'
Answer
→ Rhizopus fungus (Bread mould) reproduces by spore formation.
9. Name the method by which Paramecium reproduces. Is this method sexual or asexual ?
Answer
→ Paramecium reproduces by binary fission. It is asexual method of reproduction.
10. Name two plants :
(a) which can be grown from their broken sterns.
(b) which can be grown from their leaves.
Answer
→ (a) Bryophyllum and money plant can be grown from their broken sterns.
(b) Bryophyllum and Begonia can be grown from their leaves.
11. Name the asexual method of reproduction in yeast.
Answer
→ Yeast reproduce by budding.
12. Name the asexual method of reproduction in
(a) Hydra, and
(b) Plasmodium.
Answer
→ (a) Budding is asexual method of reproduction in hydra.
(b) Plasmodium reproduce by multiple fission.
13. What is the name of asexual reproduction method in :
(l) Spirogyra, and (ii) Leishmania?
Answer
→ Fragmentation is found in spirogyra.
14. Name the artificial propagation method used for the propagation of
(a) rose plants, and
(b) apple trees.
Answer
→ (a) Cutting is the method of artificial propagation which is used for the propagation of rose plants.
(b) Grafting is used for the propagation of apple trees.
15. Which artificial propagation method is used for the production of jasmine plants ?
Answer
→ Layering is used for the propagation of jasmine plants.
16. Name the natural method by which strawberry plants are propagated.
Answer
→ Strawberry plants are propagated by naturel layering method.
17. Name two plants which are propagated by layering method.
Answer
→ Hibiscus and Bougainvillea plants are propagated by layering method.
18. Name any two plants which are propagated by cuttings method.
Answer
→ Rose and grapes are two plants which are propagated by cuttings method.
19. Write down the different methods of asexual reproduction.
Answer
→ The different methods of asexual reproduction are:
(i) Fission
(ii) Fragmentation
(iii) Regeneration
(iv) Budding
(v) Vegetative propagation
(vi) Spore formation
20. Why are budding, fragmentation and regeneration, all considered to be asexual type of reproduction ?
Answer
→ Because in all these methods, only single parent takes part and forms new offsprings without using gametes.
21. Fill in the following blanks with suitable words :
(a) The process of..............ensures continuity of life on earth.
(b) Plasmodium reproduces by the process of ............... fission whereas Paramecium reproduces by the process of .............. fission.
(c) Rose plants and sugar cane crop are usually grown by the ................. method.
(d) Vegetative reproduction of potato plants is done by using .................
(e) Strawberry plants are propagated by the natural........................ method.
Answer
→ (a) reproduction
(b) multiple; binary
(c) cuttings
(d) tubers
(e) layering
Short Answer Type Questions-Pg-141
22A. What is the basic difference between asexual reproduction and sexual reproduction?
Amoeba, Cats, Humans, Hydra, Birds
Answer
→ Difference between asexual reproduction and sexual reproduction-
Asexual reproduction
|
Sexual reproduction
|
In this type of reproduction, the offspring arises from a single parent.
|
The offspring arises from two parents of different sexes.
|
Example: Hydra, Amoeba, etc.
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Example: Frog, human beings, etc.
|
22B. Which of the following organisms reproduce by sexual method and which by asexual method ?
Amoeba, Cats, Humans, Hydra, Birds
Answer
→ Sexual method: Cats, humans, birds
Asexual method: Amoeba and Hydra
23A. What is meant by regeneration ? Name two animals which can regenerate fully from their cut body parts
Answer
→ The process of getting back a full organism from its body parts is called regeneration. Planaria and hydra are two organisms which can be regenerated fully from their body parts.
23B. Explain why, more complex multicellular organisms cannot give rise to new organisms through regeneration.
Answer
→ Multicellular organisms have a high degree of specialized organization in their body. In their body, multiple cells make tissue, tissues make organs and organs make organ system and finally many organ systems makeup an organism. So, more complex multicellular organisms cannot be reproduced from their cut body parts by regeneration.
24. Explain vegetative propagation with the help of two examples. List two advantages of vegetative propagation.
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. Example: Bryophyllum plant reproduces from its leaves and money plant grows from its stem.
Advantages of vegetative propagation are:
•Plants grow faster by the process of vegetative propagation.
•All plants produced are genetically similar to the parent plant.
25A. What is meant by the term 'artificial propagation of plants' ?
Answer
→ The process of growing many plants from one plant by man-made methods is called artificial propagation of plants.
25B. Name three common methods which are used for the artificial propagation of plants.
Answer
→ The threes methods of artificial vegetative propagation are:
(i) Cutting (ii) Layering and (iii) Grafting
25C. Name two plants which are usually propagated by artificial propagation methods. Name the method of artificial propagation used in each case.
Answer
→ (i) Grapes grow by means of cutting. (ii) Jasmine grows by means of layering.
26. Describe the layering method for the artificial propagation of plants. Illustrate your answer with the help of a labelled diagram. Name any five plants which are propagated by the layering method.
Answer
→ In this method, one of the lower branch of the plant is bent and covered partially with moist soil. After some time, new roots develop from the part of the branch buried in the soil. The branch is then cut off from the parent plant. It grows into a new plant.
The layering method is used for the propagation of plants like Jasmine, Strawberry, Raspberry, Lemon and Guava.
27A. What is meant by the term 'fission' as used in biology ?
Answer
→ Splitting of an organism into two new organisms is called fission.
27B. How does binary fission differ from multiple fission ?
Answer
→ Difference between binary fission and multiple fission:
Binary Fission
|
Multiple fission
|
Splitting of unicellular organism like Amoeba into two equal halves during cell division is called binary fission.
|
Division of single-celled organism like Plasmodium into many daughter cells simultaneously is called multiple fission.
|
27C. Name one organism which reproduces by binary fission and another which reproduces by multiple fission.
Answer
→ Binary fission: Amoeba;
Multiple fission: Plasmodium
27D. State whether the above named organisms are animals or plants.
Answer
→ These are microscopic animals.
28A. Can you consider cell division as a type of reproduction in unicellular organisms ? Give reason.
Answer
→ We consider cell division as a type of reproduction in unicellular organism because it leads to the formation new cells.
28B. What is a clone ? Why do off springs formed by asexual reproduction exhibit remarkable similarity ?
Answer
→ The organisms which are produced asexually are genetically identical to the parent and are called clones. The basic event in the reproduction is the creation of DNA copy. The replication of DNA occurs by certain biochemical reactions which synthesize more of genetic material. When the DNA already present in the nucleus of the parent cell is replicated by making more DNA at the time of asexual reproduction then slight variations come in the two copies formed. Due to this the two DNA molecules formed will be similar but not identical.
29A. The yeast cells fail to multiply in water but they multiply rapidly in sugar solution. Give one reason for it.
Answer
→ Yeast cells fail to multiply in water because water does not provide any energy to yeast cells. Whereas in sugar solution, they multiply rapidly because sugar provide energy to carry out reproduction.
29B. Why does bread mould grow profusely on a moist slice of bread but not on a dry slice of bread ?
Answer
Moisture is necessary for the growth of bread mould. The bread mould grows profusely on moist slice of bread because it provides both moisture and nutrients for growth. The dry slice of bread provides nutrients but no moisture. So, bread mould does not grow on the dry slice of bread.
30A. What is a tuber? Name one stem tuber and one root tuber.
Answer
→ Tuber is an enlarged structure in some plant used as storage organ for nutrients.
Stem tuber : Potato ;
Root tuber : Sweet potato
30B. What is name of the organ of propagation present in a tuber?
Answer
→ This is called eyes. Each eye of potato can give rise to a new potato plant.
30C. Name one commonly used vegetable which is propagated by using tubers.
Answer
→ The vegetable which is propagated by using tubers is potatoes.
31A. What is meant by vegetative propagation ?
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.
31B. Vegetative propagation involves the growth and development of 'something' present in the old part of the plant to form a new plant. What is this 'something'?
Answer
→ Vegetative propagation involves the growth and development of buds present in the old part of the plant to form a new plant.
31C. Why do green grass plants spring up in dry fields on their own after the rains ?
Answer
→ Dry fields have dry stems of old grass all over which contains buds in an inactive state. During the rains, these buds get rain water and become active to produce new grass plants.
32A. Explain how, new Bryophyllum plants can be produced from the leaves of the old plant ? Illustrate your answer with the help of a labelled diagram.
Answer
→ Bryophyllum can be reproduced by vegetative propagation by using either a piece of its stem or leaves. The leaves of a Bryophyllum have special buds on their margins which may fall on the soil and develop into new plant.
32B. How can you grow money plant by vegetative propagation ?
Answer
→ Money plant can be grown by vegetative propagation by using a piece of its stem which contains at least one leaf on it. It is dipped into the water and after a few days new roots appear at the point where the leaf was attached. This piece of stem grows gradually into a new money plant.
33. Match the organisms given in column I with the methods of reproduction/propagation given in column II:
| Column I | Column II |
| (i) Plasmodium | (a) Spore formation |
| (ii) Spirogyra | (b) Leaves |
| (iii) Jasmine | (c) Regeneration |
| (iv) Apple tree | (d) Budding |
| (v) Bryophyllum | (e) Binary fission |
| (vi) Potatoes | (j) Layering |
| (vii) Rhizopus | (g) Fragmentation |
| (viii) Hydra | (h) Tubers |
| (ix) Planaria | (i) Cuttings |
| (x) Leishmania | (j) Multiple fission |
| (xi) Sugar cane | (k) Grafting |
| (xii) Rose |
Answer
→ (i) j (ii) g (iii) f (iv) k (v) b (vi) h (vii) a (viii) d (ix) c (x) e (xi) i (xii) i