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NEET Biology MCQ
Sexual Reproduction In Flowering Plants Mcq
Quiz 5
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Q.1
Endosperm formation is suppressed in ... .... [ AMU 1997 ]
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a) Liliaceae
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b) Cyperaceae
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c) Orchidacease and Podostemaceae
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d) Graminease
Explanation
Answer : (c)
Q.2
Select the correct and incorrect statements a) Tapetum nourishes developing pollen grains b) Hilum represents junction between ovule and funicle c) In aquatic plants. Water Hyacinth and Water Lily, pollination is by water d) Primary endosperm nucleus is triploid
0%
a) a, b correct. c, d incorrect
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b) a,b, d correct. c incorrect
0%
c) b,c, d correct. a incorrect
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d) a, d correct, b, c incorrect
Explanation
Answer : (b)
Q.3
Cleistogamous flowers are ... .. [ AMU 1997]
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a) Wind pollinated
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b) Self pollinated
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c) Cross pollinated
0%
d) Insect pollinated
Explanation
Cleistogamy is a type of automatic self-pollination of certain plants that can propagate by using non-opening, self-pollinating flowers. Answer : (b)
Q.4
Route used by pollen tube for entering ovule is .... .. [ MPPMT 2001 ]
0%
a) Integument
0%
b) Micropyle
0%
c) Chalaza
0%
d) Any of the above
Explanation
Type of entry of pollen tube - 1)porogamy-micropyle 2)chalazogamy-chalazal 3)mesogamy-integument Answer : (d)
Q.5
tion 1 In ficus pollination occurs through b) Air
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a) Water
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c) Bat
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d) Insects
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Explanation and answer
Explanation
Female fig wasps help in pollination in Ficus. They enter the Ficus via ostiole, sub-closed inflorescences to lay their own eggs and during this time pollen gets to stick to the body of wasp and thus pollination occurs. Answer:(d)
Q.6
tion 3 Pollen grains can be stored for several years in liquid nitrogen having a temperature of [NEET 2018]
0%
a) -196°
0%
b) – 80°C
0%
c) – 120°C
0%
d) – 160°C
Explanation
Pollen grain can be cryopreserved in liquid nitrogen ( temp – 196°C) and used as pollen banks. Answer:(a)
Q.7
on 201 Pollen kit is secreted by:
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a) Epidermis
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b) Endothecium
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c) Middle layers
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d) Tapetum
Explanation
Answer:(d)
Q.8
tion 4 Winged pollen grains are present in [NEET 2018]
0%
a) Mango
0%
b) Cycas
0%
c) Mustard
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d) Pinus
Explanation
The wings on the pollen grain aid in the dispersal of the pollen grains by the wind. Mango pollinators include different kinds of wasps, flies, stingless bees and even ants. mustard is basically an insect-pollinated type of crop, with ample pollen and nectar to attract pollinating insects. Cycas pollen is dry, light and round and pollinated by wind. Whereas, in pinus, pollen is winged that helps in pollination. Answer:(d)
Q.9
tion 5 How many of the following statements are true: (i) Pollenkitt is composed of lipids and carotenoids. (ii) In most of the angiosperms, microgametogenesis occurs only after pollen dehiscence. (iii) Pollinium is found in Calotropis . (iv) Bisporic embryo sac is found in Polygonum .
0%
a) One
0%
b) Two
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c) Three
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d) Four
Explanation
(i) Pollenkitt is a hydrophobic mixture of materials, composed mainly of saturated and unsaturated lipids, carotenoids, flavonoids, proteins and carbohydrates. Statement (i) is correct. (ii) Microsporogenesis is the process of formation of pollen grains (microspores) from the sporogenous tissue. Microgametogenesis is the process of formation of male gametes from the generative cell nucleus that is present inside the pollen grain through mitosis. It occurs during dehiscence of pollen. Statement (ii) is correct. (iii) In calotropis and orchids, the pollen of each anther lobe formed a characteristics mass called pollinium. Statement (iii) is correct. (iv) In bisporic development instead of four, two megaspores are produced as a result of meiosis in the megaspore mother cell. Each megaspore has two haploid nuclei. One of these degenerates, the other undergoes megagametogenesis to form the embryo sac. It is also called the Allium type of embryo sac. statement (iv) is incorrect. Answer:(c)
Q.10
tion 6 Assertion: Plumose stigma is the feathery stigma found in ornithophillous flower Reason: Helps in disperse pollen grains into distant areas
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a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion
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b) Both Assertion and Reason are true but Reason is NOT the correct explanation of Assertion
0%
c) Assertion is true but Reason is false
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d) Both Assertion and Reason are false
Explanation
Plumose stigma means feathery or hairy stigma. Such stigma is an adaption for wind pollinated flowers i.e. anemophily, as it can move due to wind to catch pollen carried by wind. Assertion and reason are false. Answer:(d)
Q.11
tion 7 Which of the following plants possess largest pollen grain and largest pollen tube respectively?
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a) Myosotis and Maize
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b) Mirabilis and Zostera
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c) Mirabilis and Maize
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d) Myosotis and Zostera
Explanation
Answer:(c)
Q.12
tion 8 An egg-apparatus contains (
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a) An egg + two antipodals
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b) An egg + Secondary nucleus
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c) An egg + Two synergids
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d) Antipodal cell + synergid
Explanation
Three cells are grouped together at the micropylar end and constitute the egg apparatus. The egg apparatus consists of two synergids and one egg cell. Answer:(c)
Q.13
tion 9 Fertilized secondary nucleus develops into
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a) Fruit
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b) Embryo
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c) seed
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d) Endosperm
Explanation
Two male gametes are discharged into embryo sac through pollen tube. One of the male gametes fuse with the egg, resulting in the production of diploid zygote. This is called syngamy or also called generative fertilization. The second male gametes fuses with two polar nuclei, producing a triploid primary endosperm nucleus. This is called triple fusion and is also known as vegetative fertilization. Answer:(d)
Q.14
ion 10 In angiosperm the endosperm is formed
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a) In the nucellus
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b) In the embryo sac
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c) In the seed
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d) In the anther
Explanation
The second male gametes fuses with two polar nuclei, producing a triploid primary endosperm nucleus. This is called triple fusion and is also known as vegetative fertilization. In an embryo sac there occur two sexual fusion – one in syngamy and other in triple fusion. This phenomenon is called double fertilization. Answer:(b)
Q.15
ion 11 When pollen grains are not transferred from anthers to stigma in a flower, due to the physical barrier, it is called
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a) Cleistogamy
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b) Herkogamy
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c) Dichogamy
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d) Heterogamy
Explanation
Herkogamy : It is the presence of natural or physical barrier between androecium and gynoecium which help in avoiding self pollination. In calotropis stignui, gynoecium is fused with pollinium and form gynostegium. Answer:(b)
Q.16
ion 12 Meroblastic developments are related to:
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a) Endosperm development
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b) Embryogenesis
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c) Megasporogenesis
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d) Microsporogenesis
Explanation
Meroblastic embryogeny is common in gymnosperms. When the part of zygote is involved in the development of embryo, this type of embryo development is called meroblastic embryogeny. In these plants embryo is developed from a portion of oospores and in such case more than two embryos can be developed(polyembryony) Answer:(b)
Q.17
ion 13 How many of the following plants produce protandrous flowers? (i) Cotton (ii) Calotropis (iii) Passiflona (iv) Ficus
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a) One
0%
b) Two
0%
c) Three
0%
d) Four
Explanation
Protandry: Anthers mature earlier. E.g, Salvia, clerodendron, sunflower, rose Answer:(a)
Q.18
ion 14 Additional embryos develop from integument or nucellus in:
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a) Citrus
0%
b) Papaya
0%
c) Maize
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d) Coconut
Explanation
The phenomenon of having more than one embryo is called polyembryony. Formation of additional embryos from different parts of ovule like synergids, antipodal, nucellus, integuments etc. Example – Citrus, groundnut, onion, opuntia, mangifera. Answer:(a)
Q.19
ion 15 The ploidy level of female gametophyte, megaspore mother cell, endothecium, inner integument, nucellus and synergids are respectively:
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a) n, 2n, n, n, 2n, n
0%
b) n, 2n, 2n, 2n, 2n, n
0%
c) 2n, n, 2n, n, 2n, n
0%
d) n, 2n, n, 2n, 2n, n
Explanation
female gametophytes are part of gametophyte and ploidy is n. megaspore mother cells are part of sporophyte so these are diploid cells and their ploidy is 2n The synergids are haploid cells and their ploidy is n. Endothecium is a layer of diploid cells and their ploidy is 2n. Nucellus(located within the integumentary) have 2n ploidy. The integument is the outer protective envelope of an ovule. It is diploid in a diploid angiosperm. and their ploidy is 2n. Answer:(b)
Q.20
ion 16 Hilum represents:
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a) Point of attachment of embryo sac and nucellus
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b) Opening of seed just above the caruncle
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c) Point of origin of integuments from chalaza in ovule
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d) Point of attachment of body of ovule and funicle
Explanation
The ovule is attached to placenta by means of a stalk called funiculus or funicle. The point of attachment of funicle to the ovule is known as hilum. Answer:(d)
Q.21
ion 17 Pollinium is seen in:
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a) Calotropis
0%
b) Annona
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c) Mimosa
0%
d) All of these
Explanation
In family asclepiadaceae and orchidacae, all the microspores in a sporangium adhere together in a single mass called pollinium. In calotropis and orchids, the pollen of each anther lobe formed a characteristics mass called pollinium. Answer:(a)
Q.22
ion 18 When a seed fail to germinate due to the absence of external/environmental factors like moisture, oxygen, optimum temperature, etc; the seeds are said to be:
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a) Quiescent seeds
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b) Dormant seeds
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c) Perennial seeds
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d) Orthodox seeds
Explanation
The key difference between quiescence and dormancy is that quiescence is the inability of a normal, non-dormant seed to germinate because of the absence of conditions suitable for germination while dormancy is an evolutionary adaptation that prevents seeds from germinating during unsuitable ecological conditions that would typically lead to a low probability of seedling survival. Orthodox seeds are seeds which will survive drying and/or freezing during ex-situ conservation. Perennials seeds are seeds that persist for many growing seasons. Answer:(a)
Q.23
ion 19 The total number of meiosis required to produce 10 pea seeds is:
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a) 10
0%
b) 12
0%
c) 13
0%
d) 2.5
Explanation
100 seeds of pea would be produced from 100 pollen. grains and 100 embryo sacs- 100 pollen grains will be formed by 25 microspore mother cells, while 100 embryo sacs will be formed by 100 megaspore mother cells Thus, number of meiotic divisions required to produce 100 seeds would be 125 number of meiotic divisions required to produce 10 seeds would be 12.5 or 13 Answer:(c)
Q.24
on 139 Which of the following is true regarding embryogenesis in angiosperms? (i) Meroblastic. (ii) Endoscopic. (iii) Occurs inside embryo sac. (iv) Only mitosis is involved.
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a) (iii) only
0%
b) (i), (ii) and (iii)
0%
c) All except (i)
0%
d) All the statements are true
Explanation
Answer:(d)
Q.25
on 140 . Identify the ploidy of archesporial cell:
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a) Haploid
0%
b) Diploid
0%
c) Triploid
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d) Polyploid
Explanation
Answer:(b)
Q.26
ion 20 Which among the following is not a product/after effect of double fertilization?
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a) Embryo
0%
b) Primary endosperm nucleus
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c) Zygote
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d) Flower
Explanation
Fertilization is defined as the fusion of male and female gametes to form the zygote which eventually develops into an embryo. Two male gametes are discharged into embryo sac through pollen tube. One of the male gametes fuse with the egg, resulting in the production of diploid zygote. This is called syngamy or also called generative fertilization. The second male gametes fuses with two polar nuclei, producing a triploid primary endosperm nucleus. This is called triple fusion and is also known as vegetative fertilization. In an embryo sac there occur two sexual fusion – one in syngamy and other in triple fusion. This phenomenon is called double fertilization. Answer:(d)
Q.27
ion 21 Which among the following statements are correct regarding the viability or structure of pollen grains? (i) Vegetative cell of pollen grain is bigger has abundant food reserve and small regularly shaped nucleus. (ii) Male gametes are formed from generative cells through meiotic division. (iii) In some cereals such as rice and wheat pollen grains lose viability within 30 minutes of their release. (iv) In some families like rosaceae, leguminosae and solanaceae, viability last for several months. (v) Palynology is the study of pollen grains.
0%
a) (i) and (ii) only
0%
b) (ii), (iii) and (iv)
0%
c) (ii) and (iii) only
0%
d) (iii), (iv) and (v)
Explanation
(i) The vegetative cell is bigger, has abundant food reserve and a large irregularly shaped nucleus. statement (i) is incorrect. (ii) The generative cell divides mitotically to give rise to the two male gametes before pollen grains are shed (3-celled stage). Statement (ii) is incorrect. (iii) In some cereals such as rice and wheat, pollen grains lose viability within 30 minutes of their release. Statement (iii) is correct. (iv)in some members of Rosaceae, Leguminoseae and Solanaceae, they maintain viability for months. Statement (iv) is incoreect. (v) The branch of study of pollens is called palynology. Statement (v) is correct. Answer:(d)
Q.28
ion 22 Identify the parts labelled and choose the correct option:
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a) 1 – Tapetum, 2 – Microspore mother cells, 3 – Middle layers, 4 – Endothecium, 5 – Epidermis
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b) 1 – Epidermis, 2 – Middle layers, 3 – Microspore mother cells, 4 – Tapetum, 5 – Endothecium
0%
c) 1 – Middle layers, 2 – Epidermis, 3 – Tapetum, 4 – Microspore mother cells, 5 – Endothecium
0%
d) 1 – Epidermis, 2 – Endothecium, 3 – Middle layers, 4 – Microspore mother cells, 5 – Tapetum
Explanation
Answer:(d)
Q.29
ion 23 Epiblast is:
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a) Outer most covering of Megasporangium
0%
b) Membranous covering of plumule in monocot embryo
0%
c) Second rudimentary cotyledon of monocot embryo
0%
d) The persistent nucellus in the seed
Explanation
Remains of second cotyledons occurs in some grasses (monocot embryology). It is called epiblast. Answer:(c)
Q.30
ion 24 Which among the following plant possess non – endospermic seeds?
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a) Oryza sativa
0%
b) Triticum aestivum
0%
c) Glycine max
0%
d) Ricinus communis
Explanation
Non-endospermic or ex-albuminous: Food stored in endosperm is completely exhausted by developing embryo. Example : Seed of gram, pea, bean, orchid. Ricinuscommunis, Triticum aestivum and Oryza sativa possess endospermic seeds. Glycine max possess endospermic seed. Answer:(c)
Q.31
ion 25 Pollen tube entering into the embryo sac through:
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a) Persistent synergids
0%
b) Degenerating synergids
0%
c) Between persistent synergids and egg cell
0%
d) Between degenerating synergids and egg cell
Explanation
The synergids have special cellular thickenings at the micropylar tip called filiform apparatus, which play an important role in guiding the pollen tubes into the synergid. Degenerated synergid is that synergid which starts degenerating at the time of pollination and its secretions attract the pollen tube towards micropyle. Persistent synergid is the other synergid that persists and starts degenerating at the time of fertilisation. Answer:(b)
Q.32
ion 26 In Commelina, which type of pollination occurs?
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a) Autogamy
0%
b) Geitonogamy
0%
c) Xenogamy
0%
d) All the above
Explanation
Cleistogamy: The flowers remain close so there is no alternative self pollination. Examples: Pisum, Lathyrus, commelina, benghalensis. Answer:(d)
Q.33
ion 27 Insect pollinated flowers are:
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a) Small, producing nectar and with dry pollen grains
0%
b) Large, producing fragrance, nectar and sticky pollen grains with pollen kit
0%
c) Large, bright coloured petals, feathery stigma and large number of pollen grains
0%
d) Small, producing fragrance, light coloured petals
Explanation
Entomophily ( Insect pollination) characteristics: (i) Flowers are coloured. Bluish-purplish – violet – yellow flowers attracts bees while reddish flowers attract butterflies and wasps. (ii) Flowers commonly posses an aroma or scent. (iii) Visiting insects are fed by either nectar and pollen. (iv) Pollen grains are sticky due to pollenkitt. (v) Stigmas are sticky. Answer:(b)
Q.34
ion 28 Pericarp and perisperm are formed by:
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a) Ovary wall and endosperm respectively
0%
b) Fruit wall and nucellus respectively
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c) Outer integuments and embryo sac respectively
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d) Ovary wall and nucellus respectively
Explanation
Wall of the ovary forms fleshy or dry fruit wall called pericarp. Perisperm is the nutritive tissue surrounding the embryo in certain seeds and developing from the nucellus of the ovule. Answer:(d)
Q.35
ion 29 On the basis of the diagram, select the correct option having correct labelling
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a) a – Filiform apparatus, b – Synergids, c – Plasma membrane, d – Egg cell, e – male gametes, f – pollen tube, g – embryo sac
0%
b) a – Filiform apparatus, b – egg nucleus, c – central cell, d – synergids, e – male gametes, f – vegetative nucleus, g – plasma membrane
0%
c) a – Filiform apparatus, b – Synergids, c – central cell, d – Egg nucleus, e – male gametes, f – vegetative nucleus, g – plasma membrane
0%
d) a – Filiform apparatus, b – egg nucleus, c – embryo sac, d – synergids, e – male gametes, f – vegetative nucleus, g – plasma membrane
Explanation
Answer:(c)
Q.36
ion 30 In Pinus, leaf cell has 2n = 12 chromosomes. What will be the number of chromosomes in its endosperm cell?
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a) 18
0%
b) 24
0%
c) 12
0%
d) 6
Explanation
endosperms in angiosperms are predominantly triploid (3n). but Pinus is exception. in pinus roots are generally diploid i.e 2n= 12. and endosperm is haploid i.e n therefore number of chromosome in endosperm is 6 Answer:(d)
Q.37
ion 31 Select the mismatch with respect to the pollinating agents:
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a) Grasses – Wind
0%
b) Water lily – water
0%
c) Yucca – Moth
0%
d) Vallisneria – water
Explanation
Water lily and water hyacinth are pollinated by insects or wind. Answer:(b)
Q.38
ion 32 The term double fertilization was coined by:
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a) Strasburger
0%
b) P. Maheshwari
0%
c) Nawaschin
0%
d) Amici
Explanation
The fusion of one sperm with the egg cell to form the embryo and of the other sperm with the polar fusion nucleus to give rise to the endosperm ('double fertilization') was discovered by Nawaschin in 1898 in the liliaceous plants, Lilium martagon and Fritillaria tenella. Answer:(c)
Q.39
ion 33 Which of the following statements are true: (i) Endothecium lie below epidermis. (ii) Fusion of egg with male gametes is called Apogamy. (iii) Synergids are haploid. (iv) Point at which the funicle touches the ovule is raphe.
0%
a) (i) and (iv) only
0%
b) (i) and (ii) only
0%
c) (ii) and (iv) only
0%
d) (i) and (iii) only
Explanation
Apogamy is formation of sporophyte or embryo directly from cells of gametophyte. One of the male gametes fuse with the egg, resulting in the production of diploid zygote. This is called syngamy. Statement (ii) is false. The point of attachment of funicle to the ovule is known as hilum. A raphe ( ridge) is formed by the fusion of funiculus with the body of ovule. statement (iv) is false. The layer below the epidermis later becomes the endothecium. Endothecium – Second wall layer usually single layered. Cells have a cellulose thickening with a little pectin and lignin. It help in anther dehiscence. Statement (i) is true. Synergids are produced by the mitotic division in the haploid megaspore of a diploid plant. So synergids of a diploid plant are haploid. Statement (iii) is true. Answer:(d)
Q.40
ion 34 In a monocotyledonous seed, the endosperm is separated from the embryo by a distinct layer called as:
0%
a) Testa
0%
b) Tegmen
0%
c) Aleurone layer
0%
d) Scutellum
Explanation
Integuments of ovule forms seed coat. Outer integuments form testa and tegmen develops from inner integuments. The single cotyledon of monocots is called scutellum. In a monocotyledonous seed, the endosperm is separated from the embryo by a distinct layer is aleurone layer. The Aleurone layer is present in the monocotyledonous endospermic seed. It surrounds the endosperm. This layer is one cell thick. Answer:(c)
Q.41
ion 35 Pollen grains lose their viability within 30 minutes of their release in:
0%
a) Rose
0%
b) Potato
0%
c) Pea
0%
d) Wheat
Explanation
In some cereals such as rice and wheat, pollen grains lose viability within 30 minutes of their release, and in some members of Rosaceae, Leguminoseae and Solanaceae, they maintain viability for months. Answer:(d)
Q.42
on 141 Which of the following does not require pollinator?
0%
a) Ornithophily
0%
b) Anemophily
0%
c) Cleistogamy
0%
d) Hydrophily
Explanation
Answer:(c)
Q.43
ion 36 Scientists are trying to transfer Apomictic genes into hybrid varieties of several of our food and vegetable crops so that:
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a) They get resistance against common pathogens
0%
b) The yield of these plants can be increased manifold
0%
c) Hybrid seeds need not be produced every year
0%
d) Their germplasm is easily stored in labs for further research
Explanation
Apomixis is the asexual production of seeds so that apomictic seeds are clones of the mother plant. Advantage of apomictic seeds to farmer: It reduces the cost of hybrid production. There is no segregation of characters in the hybrid progeny. It helps the farmer to keep using the hybrid seeds to raise new crops each year. Answer:(c)
Q.44
ion 37 Which among the following is not true about pollen grain?
0%
a) Rich in nutrients
0%
b) Many species cause severe allergies and bronchial afflictions in some people often leading to chronic respiratory disorders– asthma, bronchitis, etc
0%
c) Pollen consumption has been claimed to increase the performance race horses
0%
d) Parthenium is used against pollen allergy
Explanation
Pollen grains are rich in nutrients. Pollen consumption has been claimed to increase the performance of athletes and race horses. Pollen grains of many species cause severe allergies and bronchial afflictions in some people often leading to chronic respiratory disorders– asthma, bronchitis, etc. These statement are true. Parthenium or carrot grass that came into India as a contaminant with imported wheat, has become ubiquitous in occurrence and causes pollen allergy. Option (d) is false. Answer:(d)
Q.45
ion 38 . If the chromosome number in one cell of Aleurone layer isWhat will be the chromosome number in the following places of the same plant; Primary endosperm nucleus, synergids cell and nucellus cell?
0%
a) 24, 12, 12
0%
b) 24, 8, 16
0%
c) 12, 8, 16
0%
d) 12, 12, 16
Explanation
Ploidy of aleurone layer is 3n. 3n = 24 that implies n is 8. Primary endosperm cell is triploid i.e. 3n. Thus, it has 24 chromosomes. Synergid cell is haploid i.e. n. Thus, It has 8 chromosomes. Nucellus cell is diploid i.e., 2n. Thus it has 16 chromosomes. Answer:(b)
Q.46
ion 39 The type of cell division during microsporogenesis and gametogenesis are respectively:
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a) Mitosis and meiosis in microsporogenesis and meiosis only in gametogenesis
0%
b) Meiosis and mitosis in microsporogenesis and meiosis only in gametogenesis
0%
c) Mitosis and meiosis in microsporogenesis and mitosis only in gametogenesis
0%
d) Meiosis only in microsporogenesis and mitosis only in gametogenesis
Explanation
The formation and differentiation of microspore is called microsporogenesis. The PMCs divide meiotically each forming generally tetrahedral tetrads. Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes. For example, plants produce gametes through mitosis in gametophytes. Answer:(c)
Q.47
ion 40 . Assertion: In angiosperms, pollen grains are the male gametophyte. Reason: Pollen grains are developed from microspores and they produce male gametes.
0%
a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion
0%
b) Both Assertion and Reason are true but Reason is NOT the correct explanation of Assertion
0%
c) Assertion is true but Reason is false
0%
d) Both Assertion and Reason are false
Explanation
In flowering plants, pollen grain arefirst cells of male gametophyte. Assertion is true. The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called microsporogenesis. The microspores, as they are formed, are arranged in a cluster of four cells–the microspore tetrad. As the anthers mature and dehydrate, the microspores dissociate from each other and develop into pollen grains. Reason is true and correct explanation of assertion. Answer:(a)
Q.48
ion 41 Epiblast is:
0%
a) Rudimentary cotyledon of dicot embryo
0%
b) Rudimentary secondary cotyledon of dicot embryo
0%
c) Rudimentary secondary cotyledon of monocot embryo
0%
d) Rudimentary endosperm of monocot
Explanation
Remains of second cotyledons in monocot embryo is called epiblast. Answer:(c)
Q.49
ion 42 Consider the following statements: (i) Formation of two male gametes from a pollen grain require two mitotic divisions. (ii) In 40% angiosperms, microgametogenesis occurs before pollen dehiscence and inside the microsporangium. (iii) In angiosperms, both male gametophyte and female gametophytes are highly reduced structures and are completely dependent on sporophyte. (iv) Insects are the most important pollination agents. Of the above statements:
0%
a) All the statements are false
0%
b) All statements are true
0%
c) Only (iii) is false
0%
d) Both (i) and (ii) are false
Explanation
In over 60 per cent of angiosperms, pollen grains are shed at this 2-celled stage. In the remaining species, the generative cell divides mitotically to give rise to the two male gametes before pollen grains are shed (3-celled stage). In the seed plants (gymnosperms and angiosperms), the sporophyte is green and photosynthetic and the gametophyte depends on the sporophyte for nourishment. Within the seed plants, the gametophyte has become further reduced, with fewer cells comprising the gametophyte. Plants use two abiotic (wind and water) and one biotic (animals) agents to achieve pollination. Majority of plants use biotic agents for pollination. Answer:(b)
Q.50
ion 43 In some plants like castor and maize, both male and female flowers are present on the same plant that is monoecious, which prevents:
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a) Both Autogamy and geitonogamy
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b) Geitonogamy but not Autogamy
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c) Both geitonogamy and Xenogamy
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d) Autogamy but not geitonogamy
Explanation
Autogamy: It is a self pollination which occurs between anther and stigma of the same flower. Geitonogamy: It is transfer of pollen grain from anther of one flower to stigma of another flower of same plant or genetically similar plants. Since flowers are unisexual, it prevents autogamy but there is possibility of pollination between flowers of same plant. Answer:(d)
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