Free PDF Download of CBSE Biology Multiple Choice Questions for Class 12 with Answers Chapter 2 Sexual Reproduction in Flowering Plants. Biology MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Biology Sexual Reproduction in Flowering Plants MCQs Pdf with Answers to know their preparation level.
1. How many microspore mother cells are required to produce 1000 microspores/pollen grains?
2. Which of the following represents the female gametophyte in angiosperms?
(b) Embryo sac
3. In a breeding experiment, the selected male parent is diploid and the female parent is tetraploid. What will be the ploidy level of the endosperm that will develop after double fertilisation?
4. The development of fruits without fertilisation of the ovary, is called
5. When the pollen of a flower is transferred to the stigma of another flower on the same plant, the process is known as
6. The number of meiotic divisions, required to produce 400 seeds in a pea plant, is
7. A dicotyledonous plant bears flowers but never produces fruits and seeds. The most probable cause for the above situation is [NCERT Exemplar]
(a) plant is dioecious and bears only pistillate flowers.
(b) plant is dioecious and bears both pistillate and staminate flowers.
(c) plant is monoecious.
(d) plant is dioecious and bears only staminate flowers.
8. Autogamy can occur in a chasmogamous flower if [NCERT Exemplar]
(a) pollen matures before maturity of ovule.
(b) ovules mature before maturity of pollen.
(c) both pollen and ovules mature simultaneously.
(d) both anther and stigma are of equal lengths.
9. Choose the correct statement from the following. [NCERT Exemplar]
(a) Cleistogamous flowers always exhibit autogamy.
(b) Chasmogamous flowers always exhibit geitonogamy.
(c) Cleistogamous flowers exhibit both autogamy and geitonogamy.
(d) Chasmogamous flowers never exhibit autogamy.
10. From among the situations given below, choose the one that prevents both autogamy and geitonogamy. [NCERT Exemplar]
(a) Monoecious plant bearing unisexual flowers.
(b) Dioecious plant bearing only male or female flowers.
(c) Monoecious plant with bisexual flowers.
(d) Dioecious plant with bisexual flowers.
11. In a fertilised embryo sac, the haploid, diploid and triploid structures are: [NCERT Exemplar]
(a) Synergid, zygote and primary endosperm nucleus.
(b) Synergid, antipodal and polar nuclei.
(c) Antipodal, synergid and primary endosperm nucleus.
(d) Synergid, polar nuclei and zygote.
12. In an embryo sac, the cells that degenerate after fertilisation are: [NCERT Exemplar]
(a) Synergids and primary endosperm cell.
(b) Synergids and antipodals.
(c) Antipodals and primary endosperm cell.
(d) Egg and antipodals.
13. Which of the following floral parts forms the pericarp after fertilisation?
(b) Outer integument
(c) Ovary wall
(d) Inner integument
14. The stalk of the ovule is called _____ .
15. The outer integument of the ovule develops into _____ after fertilisation.
16. The exine of pollen grains is made up of ______ .
17. The outermost layer of endosperm in a maize grain is known as ______ .
Explaination: Aleurone layer.
18. A bisexual flower that never opens, is called ______ .
19. In the grass family, the single cotyledon is called ______ .
20. The hollow foliar structure that encloses the leaf primordia in a grass embryo, is called ______ .
21. In apple, the ______ also contributes to fruit formation and becomes edible.
22. Occurrence of more than one embryo in a seed, is known as ______ .
23. Dehydration and _____ of mature seeds are crucial for storage of seeds.
24. Match the terms in Column I with the descriptions in Column II.
|Column I||Column II|
|A. Pericarp||1. Cotyledon in the seeds of grasses.|
|B. Pollen grains of Vallisneria||2. Remains of nucellus in a seed.|
|C. Perisperm||3. Mucilaginous covering.|
|D. Scutellum||4. Wall of the true fruit.|
Explaination: A – 4, B – 3, C – 2, D – 1
25. Match the terms in Column I with the descriptions in Column II.
|Column I||Column II|
|A. Syncarpous ovary||1. Occurrence of more than one embryo in a seed.|
|B. Polyembryony||2. Carpels in a flower are fused together.|
|C. Apomixis||3. Removal of Stamens from the bisexual flower bud.|
|D. Emasculation||4. Formation of seeds without fertilisation.|
|5. Development of ovary into fruit without fertilisation.|
Explaination: A – 2, B – 1, C – 4, D – 3
26. Sepals and petals orperianth are inconspicuous in entomophilous flowers. [True/False]
27. In Zostera, the pollen grains are long and ribbon-like and released inside the water. [True/False]
28. Embryo sac → Nucellus → Integuments, is the correct sequence of parts in the ovule of an angiosperms. [True/False]
29. Conidia are formed endogenously while zoospores are formed endogenously. [True/False]
30. Meiosis does not occur in the organisms showing haplontic life cycle. [True/False]
Directions (Q31 to Q35): Mark the odd one in each of the following groups.
31. Antipodal cells, Synergids, Zygote, Female gamete
32. Zygote, Endosperm, Embryo, Persperm
33. Radicle, Plumule, Endosperm, Scutellum
34. Mango, Apple, Strawberry, Cashew
35. Epidermis, Endothecium, Middle layers, Sporogenous tissue.
Explaination: Sporogenous tissue.
36. How many microsporangia are present in a typical anther of an ar.giosperm? [Foreign 2013]
Explaination: Four microsporangia.
37. Name the innermost and outermost wall layers of a microsporangium in an angiosperm anther. [Foreign 2013]
Explaination: Tapetum is the innermost.
Epidermis is the outermost.
38. An anther with malfunctioning tapetum often fails to produce viable male gametophyte. Give any one reason. [Delhi 2013,10; HOTS]
Explaination: Since the tapetum nourishes the developing pollen grains, their development is impaired.
39. How many microspore mother cells would be required to produce one hundred pollen grains in a pollen sac? And why? [Foreign 2013]
Explaination: Twenty five microspore mother cells. Each microspore mother cell undergoes meiosis and forms four microspores.
40. AbilobeddithecousantherhaslOOmicrospore mother cells per microsporangium. How many male gametophytes can this anther produce? [Delhi 2010; HOTS]
Explaination: 1600 male gametophytes.
41. What are germ pores?
Explaination: Germ pores are those places on the exine of a pollen grain, where sporopollenin is thin or absent and gives the appearance of an aperture.
42. Give an example of a plant which came into India as a contaminant and is a cause of pollen allergy. [AI 2014]
Explaination: Parthenium (Carrot grass).
43. Mention two environmental factors that affect pollen viability. [Delhi 2011C]
Explaination: Temperature and humidity.
44. How are different varieties of pollen grains stored for long period of time in pollen banks? [AI 2017C]
Mention any one application of a pollen bank [Delhi 2011C]
Explaination: The pollen grains can be stored for years in liquid nitrogen (-196 °C) in pollen banks and used for crop breeding programmes.
These pictures show the gynoecium of (A) Papaver and (B) Michelia flowers.
Write the difference in the structure of their ovaries. [Delhi 2015C]
Explaination: – In (A) Papaver, the ovary is syncarpous, where the carpels are fused together.
– In (B) Michelia, the ovary is apocarpous, where the carpels remain free from one another.
46. What represents the (a) basal part and (b) female gametophyte of the ovule?
Explaination: (a) Chalaza represents the basal part and
(b) embryo sac, the female gametophyte.
47. How many megaspore mother cell(s) become(s) differentiated in an ovule?
Explaination: Only one megaspore mother cell becomes differentiated in an ovule.
48. When does cell wall formation start, in the organisation of the embryo sac?
Explaination: At the eight-nucleate stage.
49. Of the eight nuclei formed in the em bryo sac, six become organised into cells.
(a) What term is given to the other two nuclei?
(b) Name the cell in which they are present.
Explaination: (a) The other two nuclei are called polar nuclei.
(b) They are present in the central cell.
50. What is filiform apparatus?
Explaination: Filiform apparatus refers to the special cellular thickenings in the synergids, towards micropylar tip.
51. State the function of filiform apparatus found in mature embryo sac of an angiosperm. [Foreign 2014]
Explaination: They play an important role in guiding the pollen tube to enter one of the synergids.
52. Describe the structure of the cell (s) that guide (s) the pollen tube to enter the embryo sac. [AI 2014C]
Explaination: The synergids have filiform apparatus, the special cellular thickenings at the micropylar tip.
53. State the significance of pollination.
Explaination: Pollination brings the carrier of male gametes, i.e. pollen to the stigma of the pistil.
54. Why are cleistogamous flowers invariably autogamous?
Explaination: Cleistogamous flowers are the bisexual flowers which do not open at all even at maturity and their stamens and stigma are never exposed for xenogamy or geitonogamy; the anthers and stigma lie close to each other and self pollination is effected easily.
55. How is it possible in Oxalis and Viola plants to produce assured seed-sets even in the absence of pollinators? [Foreign 2012: HOTS]
Pea flowers produce assured seed-sets. Give a reason. [AI 2010; HOTS]
Explaination: Oxalis and Viola or pea produce cleistogamous flowers, in which anthers and stigma lie close to each other; when the anthers dehisce in the flower buds, the pollen grains fall on the stigma and fertilization is effected leading to assured seed-set.
56. Give the technical term for the type of pollination
(a) which ensures genetic recombination.
(b) between different flowers of the same plant
Explaination: (a) Xenogamy.
57. The following statements describe the wind-pollinated plants. Which one of these statements is incorrect? [CBSE Sample Paper 2013]
(a) The pollen grains are sticky.
(b) Stamens are well-exposed.
(c) Flowers often have single ovule.
Explaination: (a) The pollen grains are sticky.
58. Mention the pollinating agent of an inflorescence of small dull-coloured flowers with well-exposed stamens and large feathery stigmas. Give any one characteristic of pollen grains produced by such flowers.
Explaination: – Wind is the pollinating agent.
– The pollen grains are light and non- sticky/dry.
59. Name the part of the flower, which the tassels of the com cob represent. [A t 2014]
Explaination: Styles and stigmas.
60. Why do com cobs have long tassels? [AI 2010C; HOTS]
Explaination: The long tassels of com cob are the styles and stigmas; they are meant to easily trap the air-bome pollen grains.
61. Name two groups of plants where water is the medium for transport of male gametes. [AI 2010C; HOTS]
Explaination: Bryophytes and pteridophytes.
62. How do the pollen grains of Vallisneria protect themselves? [AI 2012]
Explaination: Pollen grains of Vallisneria are protected from wetting by the mucilaginous covering.
63. The following statements (i), (ii) and (iii) . seem to describe the water-pollinated submerged plants. Which one of these statements is incorrect?
(i) The flowers do not produce nectar.
(ii) The pollen grains have mucilaginous covering.
(iii) The brightly-coloured female flowers have long stalks to reach the surface.
Explaination: (iii) is incorrect.
64. How do flowers of Vallisneria get pollinated? [Foreign 2013]
Explaination: Vallisneria shows true hydrophily, i.e. pollination by water.
65. Why do the pollen grains of Vallisneria have a mucilaginous covering?[Delhi 2010C; HOTS]
Explaination: The mucilaginous covering protects the pollen grains from wetting and the consequent decay.
66. Mention the pollinating agents for aquatic plants, Vallisneria and water lily, respectively. [AI 2010C]
Explaination: Vallisneria is pollinated by water and water lily is pollinated by insects.
67. What are nectar/pollen robbers?
Explaination: Nectar/pollen robbers are those floral visitors which consume pollen or nectar without bringing about pollination.
68. What is meant by ‘self-pollen’?
Explaination: ‘Self-pollen’ means the pollen grains from the same flower (as of the stigma) or pollen from other flowers of the same plant.
69. How is fertilisation by a self-incompatible pollen prevented?
Explaination: Fertilisation by a self-incompatible pollen is prevented by:
(a) inhibiting the germination of the pollen.
(b) retarding the growth of the pollen tube.
70. What is pollen-pistil interaction and how is it mediated? [Foreign 2014]
Explaination: – All those events from the deposition of pollen on the stigma till the entry of pollen tube into the ovule, are collectively referred to as pollen-pistil interaction.
– It is mediated by the interaction of chemicals secreted by the pollen and the stigma.
71. The meiocyte of rice has 24 chromosomes.
Write the number of chromosomes in its endosperm. [Delhi 2013C; HOTS]
Explaination: 36 chromosomes.
72. What happens to the endospenn in seeds like castor?
Explaination: It is used by the embryo for nutrition during seed germination.
73. Fill in the blanks a and b
Zygote → a → Globular embryo → b → Mature embryo.
Explaination: (a) Proembryo
(b) Heart-shaped embryo
74. Identify ‘A’ in the figure showing a stage of embryonic development in a dicot plant and mention its function. [AI 2016C]
Explaination: ‘A’ represents the cotyledons.
– Cotyledons have reserve food materials that are used by the embryo during germination of the seed.
75. Mention the common function that cotyledons and nucellus perform.
Mention the common function that endosperm and perisperm perform.
Explaination: They help in the nourishment of the embryo, with the reserve food materials stored in them.
76. Name the part of the flower that contributes to fruit fonnation in strawberry and guava respectively.
Explaination: Thalamus in strawberry and ovary in guava.
77. Why is banana referred to as a parthenocarpic fruit? [AI 2013C]
Why is banana considered a good example of parthenocarpy? [AI 2012; HOTS]
Explaination: Banana fruit develops without fertilisation of the ovary; hence it is considered parthenocarpic.
78. Banana produces fruits, but is propagated only by vegetative means. Why is it so? [Foreign 2012: HOTS]
Explaination: – Banana produces fruit without fertilization of ovary; the process is known as parthenocarpy.
– Since, parthenocarpic fruits are seedless or the seeds are non-viable, banana is propagated by vegetative means.
79. Given below is a section of a maize grain. Identify ‘A’ and state its function.[AI 2016C]
Explaination: ‘A’ represents the endosperm.
– It stores food materials, which are used by the embryo during seed germination.
80. Mention two advantages of seeds to man,
Explaination: Two advantages of seeds to man:
(i) Seeds are stored and used as food.
(ii) They are used to raise the crop.
81. How does a farmer use the dormancy of seeds to his advantage?
Explaination: Dormancy and dehydration are crucial for storage of seeds; the farmer dehydrates the dormant seeds and stores the seeds for raising a new crop in the next season.
82. Name the seeds that have retained their viability for thousands of years.
Explaination: Lupinus arcticus and Phoenix dactylifera.
83. Name two parasitic species of plants that produce many minute seeds in a fruit.
Explaination: Orobanche and Striga.
84. Name the mechanism responsible for the formation of seed without fertilisation in angiosperms. Give an example of a species of flowering plants with such seed formation. [Delhi 2010C]
Explaination: Apomixis is the phenomenon e.g. grasses, Citrus, mango and members of Asteraceae. (any one)
85. Normally one embryo develops in one seed, but when an orange seed is squeezed, many embryos of different shapes and sizes are seen. Mention how it has happened. [Delhi 2011]
Explaination: – Orange shows polyembryony, the phenomenon of occurrence of more than one embryo in a seed.
– In this case, some of the nucellar cells surrounding the embryo sac start dividing, protrude into embryo sac and develop into embryos.
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