Ans:
| Sexual reproduction | Sexual reproduction |
1. Both the parents i.e. male and female are involved. | 1. Only one parent is involved. Variation does not occur. |
| 2. A variation occurs which resultsin the formation of new species. | 2. A variation occurs which resultsin the formation of same species. |
2. The offspring produced by asexual and sexual reproduction process are dissimilar, why?
Ans: In asexual reproduction, crossing over does not take place and gametes are not involved. So, offspring produced by asexual reproduction are genetically identical to the parent. But in the case of sexual reproduction, crossing over takes place during the formation of gametes which results in the variation in the offsprings.
3. Define sexual reproduction.
Ans: The reproduction which takes place by the fusion of male gamete and female gamete is called sexual reproduction.
4. Define multiple fission.
Ans: The process in which one parent body divides into more than two daughter organisms under unfavourable condition is called multiple fission.
5. Define binary fission.
Ans: The process in which one parent body divides into only two daughter organisms during the favourable condition is called binary fission.
6. Define vegetative propagation.
Ans: The process in which the vegetative parts of plants such as roots, stem and leaves take part in the formation of new plants is called vegetative propagation.
7. What is fertilization?
Ans: The process of fusion of male and female gametes is called fertilization.
8. What is external fertilization?
Ans: The fertilization which takes place outside the body of female is called external fertilization.
9. What is internal fertilization?
Ans: The fertilization which takes place inside the body of female is called internal fertilization.
10. What is pollination?
Ans: The transfer of pollen grains from anther to stigma is called pollination.
11. What is self-pollination?
Ans: The transfer of pollen grains from anther to stigma within the same flower without any agent is called self-pollination.
12. What is cross-pollination?
Ans: The transfer of pollen grains from the anther of one flower to the sigma of another flower is called cross-pollination.
13. What is budding?
Ans: The process in which an outgrowth or bud is produced from the parent body is called budding.
14. What is regeneration?
Ans: The process in which a parent body breaks into two or more fragments and each fragment develops into a new individual is called regeneration.
15. What is grafting?
Ans: The process by which a new plant can be grown by inserting a branch or stem of a plant on another plant body is called grafting.
16. Define ovum.
Ans: Ovum is a female gamete produced in female sex organ after meiosis.
17. Define sperm.
Ans: Sperm is a male gamete produced in male sex organ after meiosis.
18. Define isogametes.
Ans: Isogametes are those gametes which do not differentiate into male and female by structure but work as opposite sex cells.
19. Define zygote.
Ans: Zygote is a fertilized ovum having diploid number of chromosomes.
20. Define fragmentation.
Ans: The process in which a multicellular organism breaks into two or more daughter organisms is called fragmentation.
21. Define unisexual organisms.
Ans: The organisms in which male and female reproductive organs are found in separate individuals are called unisexual organisms.
22. Define bisexual organisms.
Ans: The organisms in which male and female reproductive organs are found in the same individual are called bisexual organisms.
23. Define double fertilization.
Ans: The process in which two male gametes fuse with different female nuclei in the embryo sac is called double fertilization.
24. What is the major characteristic of a sexual reproduction?
25. Name the type of reproduction in Bryophyllum and Planeria.
Ans: Bryophyllum reproduces through leaves i.e vegetative propagation. Planeria reproduces through regeneration.
26. What is tissue Culture?
Ans: It is a modern technique of producing new plants from a small piece of plant tissue (explant) in a culture medium.
27. Differentiate between Scion and Stock.
Ans:
| Stock | Scion |
1. The plant whose root system is taken is called stock. | 1. The plant whose shoot system is taken is called Scion.
|
| 2. A stock is selected for its adaptabilities like strength and absorbing system. | 2. A Scion is selected for good quality of fruits and flowers. |
28.
Study the given diagram and answer the following questions.
a. What type of reproduction is shown in the diagram?
b. Write the name of A and B.
c. Name any two organisms in which such phenomenon occurs.
Ans: a. The diagram shows the asexual reproduction ie. Sporulation.a. What type of reproduction is shown in the diagram?
b. Write the name of A and B.
c. Name any two organisms in which such phenomenon occurs.
b. A is sporangium.
B is spore.
c. This type of reproduction occurs in Mucor and Mushroom.
29. How does the reproduction occur in higher animals?
Ans: In case of higher animals, sexes are separated. Both male and females are involved in reproduction. So, the reproduction is sexual reproduction. The male produces sperm cells and female produces the egg cells during male and female gametes fuses to form a zygote.
30. Bee farming was done in a village along with the cultivation of mustard. But all the bees died in one particular year and the production of mustard also decreased, why did that happen?
Ans: Bees are the pollinators i e. they help in transferring the pollen grains from anther to stigma of the same or different mustard plants. Such process helps in the reproduction which ultimately increases the production of mustard. But when all the bees died, the pollination was decreased that resulted the decrease in the production of mustard.
31. A new rose plant is grown by planting a piece of its stem in the soil. What type of reproduction is it? Why is such type of reproduction more beneficial ?
Ans: This type of reproduction is called vegetative propagation by stem (Asexual reproduction).
Such type of reproduction is more beneficial due to the following reasons:
1. A large number of plants can be propagated in as short period of time.
2. The plants which do not produce viable seeds like a rose, sugarcane, potato, etc. can easily be produced by this method.
32. Cross-pollination is considered to be superior to self-pollination, why?
Ans: The hybrids (organisms) provided as a result of cross-pollination are more healthy, vigorous and generally better adapted in the environment in which they live. Therefore, cross-pollination is considered to be superior to self-pollination.
33. What is reproduction?
Ans: Reproduction is a biological process by which living organisms produce individual of their own kind.
34. Name any four method of asexual reproduction.
Ans: The four method of asexual reproduction are:
1. Fission
2. Budding
3. Sporulation
4.Vegetative propagation
35. Which parts change into seed and fruits after fertilization?
Ans: The ovule changes into seed and ovary change into fruit.
36. Define fertilization.
Ans: The process of fusion of nuclei of male and female gamete to form a zygote is called fertilization.
37. Write a significance of sexual reproduction.
Ans: Sexual reproduction gives variation which helps in the evolution.
38. There would not be varieties of plants and animals in the world if there was no sexual reproduction. Justify.
Ans: Sexual reproduction involves the fusion of chromosomes in the nuclei of gametes more precisely; it involves the transmission of favourable variation from generation to generation which causes evolution. Due to this many types/variation of plants and animals are present in the world.
39. Differentiate between self pollination and cross pollination?
Ans:
| Self pollination | Cross pollination |
| 1. It is the process of transfer of pollen grain from another to the stigma of the same flower. | 1. It is the process of transfer of pollen grains from the anther of the flower to the stigma of another flower in the same plant or different plant of the same species. |
| 2. It does not bring variation In offsprings. | 2. It brings variation in offsprings. |
40. Write two differences between internal fertilization and external fertilization.
Ans:
Internal fertilization | External fertilization |
1. It takes place inside the female body. | 1. It takes place outside the female body. |
| 2. It takes place in lower vertebrates such as Pisces and amphibians. | 2. It takes place in higher vertebrates such as reptiles, aves and mammals. |
41. Double fertilization occurs in higher angiosperms. Justify.
Ans: In the higher angiosperms two pairs of nuclei fuse in them out of the two pollen grains, one of them fuses with egg nucleus to form embryo while the other (pollen grains) fuses with the secondary nucleus to form endosperm. So, double fertilization occurs in higher angiosperms.
42. Reproduction is advantageous to living beings, why?
Ans: Reproduction is necessary for the preservation and more in a population of a species. Reproduction is any means of preserving the species as it maintains the population. Species would be extinct once they die if there was no such process i e. Reproduction. Therefore, it is advantageous to living beings for the preparation/continuation of the generation.
43. Write down the significance of asexual reproduction?
Ans: 1. It produces new individual having exactly identical qualities as that of parent.
2. It is faster, cheaper and easier method of reproduction.
3. It is useful method of reproduction for the plants which do not produce viable seeds.
4. Off springs produced by this method get ready for further reproduction fast.
44. What is meant by triple fission? Draw a well labelled diagram showing fertilization in angiosperm.
Ans: In the flavering plants, during fertilization the male gamete fuses with the diploid secondary nucleus. The secondary nucleus is the fusion product of two polar nuclei and forms the endosperm nucleus. This process is called triple fusion.
OR
The process or by which endosperm nucleus is formed by the fusion of male gamete with the diploid secondary nucleus is called triple fusion.
45. Define budding.
Ans: Budding is the method of asexual reproduction which takes place by the formation of bud.
46. Write the name of any two plants which reproduce by vegetative propagation.
Ans: Sugarcane and Rose reproduce by vegetative propagation.
47. Name any two artificial method of vegetative propagation.
Ans: Grafting and layering are an artificial method of vegetative propagation.
48. Write one advantage of artificial vegetative propagation.
Ans: Artificial vegetative propagation is a cheaper, easier and faster method of propagation of plants.
49. What is grafting?
Ans: It is the artificial method of vegetative propagation in which two branches of different plants of closely related varieties are joined together.
50. "Vegetative propagation is beneficial to the farmers." Give any two reasons to justify this statement.
Ans: Vegetative propagation is beneficial to farmers because of the following reasons.
1. A large number of plants can be propagated easily and cheaply within a short period of time.
2. The plants like a rose, sugarcane, potato, etc. which does not produce viable seeds can easily be produced by this method.
51. Sugarcane is planted by cutting into pieces. What type of reproduction is it? Give three reasons for applying this method in sugarcane.
Ans: It is a type of asexual reproduction i.e. Vegetative propagation.
The three reasons for applying this method in sugarcane are:
1. It is an easier, cheaper and rapid method of reproduction or propagation of plants.
2. Sugarcane does not produce viable seed.
3. To get, the same variety year after year.
52. Write down three applications of tissue culture technique.
Ans: The three applications of tissue culture techniques are:
1. For the production of valuable compounds like plants derived protein used as biopharmaceuticals.
2. To cross distantly related species so as to obtain the hybrid.
3. To conserve rare or endangered plant species.
53.
Study the given diagram and answer the following questions.
Figure (a).
Figure (b)
Figure (c).
a. Which one of them shows vegetative propagation? Name this method.
b. What is the name of the animal shown in b? Name the method of reproduction shown in figure b and c?
c. Name the organism shown in c.
d. Name A and B.
Ans: Figure (a).
Figure (b)
Figure (c).
a. Which one of them shows vegetative propagation? Name this method.
b. What is the name of the animal shown in b? Name the method of reproduction shown in figure b and c?
c. Name the organism shown in c.
d. Name A and B.
a. Figure (a) shows vegetative propagation. This method is called whip grafting.
b. It is amoeba. The method of reproduction shown by b is binary fission and by c is budding.
c. It is yeast.
d. A is mother yeast.
B is a bud.
54. Differentiate between sexual and asexual reproduction.
Ans:
| Sexual reproduction | Sexual reproduction |
1. Both the parents i.e. male and female are involved. | 1. Only one parent is involved. Variation does not occur. |
| 2. A variation occurs which resultsin the formation of new species. | 2. A variation occurs which resultsin the formation of same species. |
55. The offspring produced by asexual and sexual reproduction process are dissimilar, why?
Ans: In asexual reproduction, crossing over does not take place and gametes are not involved. So, offspring produced by asexual reproduction are genetically identical to the parent. But in the case of sexual reproduction, crossing over takes place during the formation of gametes which results in the variation in the offsprings.
.