Sexual reproduction in flowering plants class 12 MCQs
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| Sexual reproduction in flowering plants class 12 MCQs |
1. Perisperm is-
(a) Degenerate secondary nucleus
(b) Remnant of nucleus
(c) Peripheral part of endosperm
(d) Degenerate synergids
2. Which of the following fruit is a case of parthenogenesis?
(a) Fruit without seeds after pollination
(b) Fruit with seeds afterpollination
(c) Fruit with viable seeds without fertilization
(d) Fruit with viable seeds after fertilization.
3. If an endosperm cell of an angiosperm has 24 chromosomes, the root cell of megaspore mother cell should have-
(a) 8 (b) 16 (c) 4 (d) 24
4. How many meiotic divisions are needed for forming 100 grains of wheat?
(a) 100 (b) 25 (c) 50 (d)20
5. Aleurone layer is present in
(a) The peripheral part of scutellum (b) The peripheral part of coleoptile
(c) Cotyledons (d) The peripheral part of endosperm.
6. Which is the most logical sequence with reference to life cycle of angiosperm?
(a) Pollination, fertilization, seed formation, germination
(b) Germination, endosperm formation, seed dispersal, double fertilization
(c) Cleavage, fertilization, grafting, fruit formation
(d) Maturation, mitosis, differentiation, fertilization.
7. Sporopollenin is secretedby
(a) Cytoplasm of the pollen
(b) Cytoplasm of the pollen mother cell
(c)Cytoplasm of the tapetum
(d) Cytoplasm of the endothecium
8. Which one of these tissues is not produced from the embryonic mass of a dicotyledonous seeds?
(a) Root tip (b) Plumule (c) Hypocotyl (d) Cotyledons
9. If the flowering plant has 12 number of chromosomes in each of its meristematic cell, which of the following structures would have 6 chromosomes?
(a) Root apex (b) Pollen and megaspore mother cells
(c) Microspore and functional megaspores (d) Secondary nucleus within the embryo.
10. The development of helobial endosperm is
(a) Just like that of cellular endosperm
(b) Exactly similar to that of nuclear endosperm
(c) Intermediate between the nuclear and cellular endosperm
(d) None of the above.
11. Embryo sac of an angiosperm is homologousto
(a) Megaspore (b) Female gametophyte
(c) Sporangium (d) None of above.
12. Anthesis is-
(a) Dehiscence of anthers
(b) Opening of floral bud
(c)Entry of pollen tube into ovule
(d)Emergence of anthers
13. Entry of pollen tube through micropyle is called
(a) Mesogamy (b) Pseudogamy (c) Chalazogamy (d) Porogamy.
14. The outermost and innermost wall layers of microsporangium in an anther are respectively
(a) Endothecium and tapetum (b) Epidermis and endodermis
(c) Epidermis and middle layer (d) Epidermis and tapetum.
15. In a fertilized embryo sac, the haploid, diploid and triploid structures are-
(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
16. Milky water in green coconut is
(a) Free nuclear Liquid endosperm
(b) Liquid female gametophyte
(c) Liquid nucleus
(d) Liquid chalaza
17. A plant with both male and female flowers is
(a) Unisexual (b) Bisexual (C) Monoecious (d) Dioecious.
18. Filiform apparatus occurs in
(a) Synergids (b) Antipodals
(c) Egg nucleus (d) Secondary nucleus.
19. A dicotyledonous plant bears flowers, but never produces fruits and seeds. The most probable cause for the above situation is
(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
20. 256 microspores will form by the meiosis of-
(a) 512 microspore mother cells (b) 128 microspore mother cells
C) 64 microspore mother cells (d) 48 microspore mother cells
21. If a normal plant suddenly started reproducing parthenogenetically, the number of chromosomes of the second generation compared to the parent will be
(a) One-half (b) One fourth (c)Double (d) Same.
22. In a flower, if the megaspore mother cell forms megaspores without undergoing meiosis and if one of the megaspores develops into an embryo sac, its nuclei would be
(a) Haploid (b) Diploid
(C) A few haploid and a few diploid (d) With varying ploidy
23. In an embryo sac, the cells that degenerate after fertilization are:
(a) Synergids and primary endosperm cell (b) Synergids and antipodals
(c) Antipodals and primary endosperm cell (d) Egg and antipodals,
24. In the embryos of a typical dicot and a grass, true homologous structures are:
(a) Coleorhiza and coleoptile (b) Coleoptile and scutellum
(c) Cotyledons and scutellum (d) Hypocotyl and radicle
25. While planning for an artificial hybridisation programme involving dioecious plants, which of the following step would NOT be relevant:
(a) Bagging of female flower (b) Dusting of pollen on stigma
(c)Emasculation (d) Collection ofpollen.
26. Choose the correct statement from thefollowing
(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.
27. Autogamy can occur in a chasmogamous flower if
(a) pollen matures before maturity of ovule
(b) ovule matures before maturity of pollen
(c) both pollen and ovules mature simultaneously
(d) both anther and stigma are of equal lengths.
28. A particular species of plant produces light, non-sticky pollen in large numbers and its stigmas are long and feathery. These modifications facilitate pollination by
(a) insects (b) water (c)wind (d) animals.
29. From among the situations given below, choose the one that prevents both autogamy and geitonogamy
(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.
30. Starting from the innermost part, the correct sequence of parts in an ovule is
(a) egg nucellus, embryo sac, integument (b) egg, embryo sac, nucellus, integument
(c) embryo sac, nucellus, integument, egg (d) egg, integument, embryo sac, nucellus
Assertion and Reasoning based Questions
In each of the following questions, a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements mark the correct answer as:
(a) Both Assertion and Reason are true and the reason is the correct explanation of the Assertion.
(b) BothAssertion andReason are true and the reason is notthe correct explanation oftheAssertion.
(c) Both Assertion and Reason are true and the reason is the correct explanation ofthe Assertion.
(d) Both Assertion and Reason are true and the reason is the correct explanation of the
Assertion.
31. Assertion. Maize is an albuminous seed.
Reason. Its endosperm is completely absorbed by its growing embryo.
32. Assertion. The megaspore mother cells divide by meiotic division to produce four spores.
Reason. Megaspore Mother Cells (MMC) are diploid and megaspores are haploid.
33. Assertion. 7-called, 8 nucleate and monosporic embryo sac is Most common type of embryo sac in dicotyledonous plants.
Reason. It was discovered first time in plant Polygonium.
34. Assertion. Female gametophyte in angiosperm is eight nucleate.
Reason. Double fertilization occurs in angiosperms
35. Assertion. Parthenogenesis is an apomixis where seeds are developed from unfertilized female gamete.
Reason. Parthenogenesis always occurs by the application of chemicals.
36. Assertion. Pollen grains, in case of hydrophily, are covered by mucilaginous/oily layer.
Reason. Mucilaginous is a viscous sticky substance that protects the pollen from water.
37. Assertion. Exine of pollen grain is comprised of sporopollenin which is resistant to high temperature, strong acid oralkali.
Reason. Sporopollenin is absent in the region of germ pore.
38. Assertion. In Ophrys one petal of the flower bears an uncanny resemblance to the female bee.
Reason. Two closely related species competing for the same resource can coexist simultaneously.
39. Assertion. Majority of insect-pollinated flowers are large, colourful, fragrant and rich in nectar.
Reason. Insects are attracted to flowers by colour, fragrance and or nectar.
40. Assertion.The continuedself-pollinationresults ininbreedingdepression.
Reason. The devise to present self-pollination is the production of bisexual flowers.
Case Based Questions
1. Read the following and answer questions given below from (i) to (v) 5
In major approaches of crop improvement programme as in crossing experiments, it is important to make sure that only the desired pollen grains are used for pollination and the stigma is protected from contamination from unwanted pollens. So, if the female parent bears bisexual flowers, removal of anthers from the flower bud before the anther dehisces is necessary (Emasculation). Emasculated flowers have to be covered with bags of suitable size to prevent contamination of their stigma with unwanted pollen-bagging. When the stigma of bagged flower attains receptivity, mature pollen grains collected from anthers of the male parent are dusted on the stigma and the flowers are re-bagged and the fruits are allowed to develop. If the female parent produces unisexual flowers, there is no need for emasculation.
(i) While planning for an artificial hybridisation involving dioecious plants, which of the following steps would not be relevant?
(a) Bagging offemale flower (b) Dusting of pollen on stigma
(c) Emasculation (d) Collection of pollen
(ii) Assertion- If the female parent produces unisexual flowers, there is noneed of emasculation
Reason- Emasculation is the removal of anthers from the flower bud before the anther dehisces.
(a) Both assertion and reason are true, and reason is the correct explanation of assertion.
(b) Both assertion and reason are true, but reason is not the correct explanation of the assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false.
(iii) Artificial hybridization denotes to
(a) production of seedless fruits (b) evolve seeds without fertilization
(C)crop improvement programme (d) occurrence of more than one embryo in a
(iv) The correct sequence to perform artificial hybridization is
(a) Bagging--)Emasculation --) Re-bagging --) Cross pollination
(b) Emasculation --)Bagging--)Cross pollination--) Re-bagging
(c) Cross pollination--) Emasculation--) Bagging --)Re-bagging
(d) Bagging--)Re-bagging--) Cross pollination--) Emasculation seed
(v) Bagging technique in artificial hybridization approach is done
(a) To prevent contamination of stigma with unwanted pollens
(b) After the anthers have been dehisced
(c) Only in monoecious plants
(d) To promote production of apomixis.
2. Read the following and answer questions given below from (i) to (v)
Pollen grains are generally spherical shaped and each is surrounded by two layers – exine and intine. Exine is made up of sporopollenin which is resistant to high temperatures and strong acids and alkali. Sporopollenin remains absent at germ pores. Pollen grains are well preserved as fossils because of the presence of sporopollenin. The inner wall of pollen grain is intine.The pollen grains are mainly shed at 2-celled stage- vegetative cell and generative cell when they are matured. Pollen grains of many species cause severe allergies and bronchial afflictions, leading to chronic respiratory disorders. It is mentioned that Parthenium or carrot grass that came into India as contaminant with imported wheat, has become ubiquitous in occurrence and causes pollen allergy. However, pollen grains are rich in nutrients which are used pollen tablets as food supplements. In western countries, large number of pollen products in the form of tablets and syrups are available in the market which are claimed to increase the performance of athletes and race horses.
(i) Assertion- Sporopollinin is an oxidative polymer of carotenoids which helps in fossilization.
Reason- Sporopollinin is a tough substance that provides resistant to biological decomposition, high temperature and alkali.
(a) Both assertion and reason are true, and reason is the correct explanation of assertion.
(b) Both assertion and reason are true, but reason is not the correct explanation of the assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false.
(ii) Which of the following statements is not appropriate for pollen grains
(a) Pollen grains can be stored for years in liquid nitrogen and can be used in crop breeding programmes,
(b) Pollen grains are rich in nutrients and can be used as pollen tablets as food supplements.
(c) Bee pollen are available in western countries in the form of tablets.
(d) Pollen consumption has potential inhibitory action which results in decreased energy in athletes and race horses.
(iii) Pollen allergy is common in many people during spring, summer and fall as plants release tiny pollen grains in tremendous quantity. Which of the following is not associated with pollen allergy?
(a) Sneezing, stuffy nose and watery, eyes (b) Asthma, bronchitis
(c) Cough, itchy nose, roof of mouth or throat (d) Fever, diarrohea and vomiting
(iv) Which of the following set does not cause allergy?
(a) Ragweed parthenium (b) Sagebrush
(c) Amaranthes (pigweed) (d) Acacia.
(v) The function of germ pore in pollen grain is
(a) Emergence of radicle (b) Absorption of water for seed germination
(c) Initiation of pollen tube (d) All of these
3. Read the following and answer questions given below from (i) to (V)
A flower of tomato plant following the process of sexual reproduction produces 240 viable seeds. The viable seeds are those which have the ability to remain alive and may develop into plants and reproduce themselves in the given appropriate conditions. This happens when one of the pollen grain reaches to the stigma by any agency at 2-celled stage vegetative cell and generative cell. The generative cell divides mitotically and forms two male gametes which enters into ovule after passing through pollen tube and undergoes the process of double fertilization in the ovule. The ovule is a large parenchymatous body formed in the ovary by megasporogenesis. The megaspore mother cell in an ovule diploid structure which undergoes meiotic division and forms one functional megaspore. The megaspore undergoes three subsequent divisions and forms 8 nuclei arranging themselves in 3 groups. After fertilization, the ovule converts into the seed and whole ovary develops into a complete fruit.
i) The minimum number of pollen grains that must have been involved in the pollination of its pistil are…………….
(a) )60 (b) 120 (c) 180 (d) 240
(ii) The minimum number of microspore mother cells must have undergone reductional division prior to dehiscence of anther are:
(a) 60 (b)90 (c) 180 (d) 240
(iii) The male gametes that might have involved in this case are:
(a) 120 (b) 240 (c)360 (d) 480
(iv) The minimal number of ovules present in the ovary would be:
(a) 60 (b) 120 (c) 180 (d) 240
(v) Megaspore mother cells involved in this process are
(a) 120 (b) 180 (c) 240 (d) 360
Answer Key
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